Saturday, September 30, 2006
New guidelines for variable speed drives + motors
The rapid rate of development of variable speed drives and motors brings with it many challenges for manufacturers, installers and users. Variable speed AC drives are now being designed in to equipment and plant in ever increasing numbers, fuelled by the two key benefits of costs reduction (through energy saving and lower maintenance demands) or process improvements (better product quality, higher dynamics, more flexible production etc). Many modern automated production systems, batch processes and continuous manufacturing operations, such as web printing, rely on the accurate control of motor/drive systems.
As industry demands ever more precision and power, at reduce cost of purchase and operation, so motor and drive producers are striving to build components and sub systems that deliver the expected performance.
While the connection between motor and inverter supply is usually straightforward, there are still a number of issues which need to be carefully considered.
Whilst the vast majority of VSD driven motors are applied without issue, some special cases require additional guidance.
To date, little independent advice on handling such issues has been available.
Some information on the motor is available from the technical report IEC34 -17 1998 "Guide for the application of cage induction motors fed from converters", but this does not reflect current state of the art and is inadequate for modern inverters.
A little further guidance on VSD issues may be obtained from BS EN 61800-2 " Adjustable speed electrical power drive systems - Part 2: General requirements".
Users may therefore feel that an important area has lacked clear guidance so far.
Considerable work relating to the characterisation and specification of cage induction motors and variable frequency converter supplies is being pioneered here in the UK, by a joint working group comprised of industry experts.
Both GAMBICA, the Association for the Instrumentation, Control and Automation Industry, and REMA, the Rotating Electrical Machines Association, have been working on standards and guidelines relating to motors and variable speed drives (VSD).
However, although both associations were working independently towards the same ultimate objective, it fell to Steve Barker (product marketing manager for variable speed drives) at Siemens Automation and Drives in Manchester, to suggest that they teamed up and formed a joint technical committee.
Mr Barker, who is Chair of the GAMBICA Association's VSD Group, explains: "Although it seemed obvious that GAMBICA and REMA should pool their expertise, the idea did appear to be somewhat revolutionary at the time it was suggested."
The concept was enthusiastically embraced by the manufacturers and a taskforce (also convened by Steve Barker) was commissioned to investigate the issue of motor insulation under inverter operation.
The results of the groups joint efforts can already be seen, with the publication of their first Technical Guide, entitled: "Variable Speed Drives and Motors: Motor Insulation and PWM Inverter Drives".
The guide, which is the forerunner to a much more detailed technical report (also now available) on the subject, is one of a series of planned publications that will provide OEM equipment designers, systems integrators and end users with help on the correct selection and use of motor/drive systems.
The co-operation between GAMBICA and REMA has not gone unnoticed internationally.
Through the various international connections of both REMA and GAMBICA, the IEC (International Electrotechnical Commission), who are responsible for setting so many of the product standards now found in factory automation and process control, have also taken up the challenge.
Previously, one IEC committee concerned itself with motors another group concentrated on drives and power electronics.
Impressed with what they saw happening in the UK, the two IEC committees took the decision to create a joint working group to address the specific issues applicable to motors designed to be operated from inverter supplies.
The working group consists of nearly twenty international experts active in the field of both drives and motors.
Together with end users, most of the major manufacturers are represented with delegates from across Europe, North America and Japan.
Based on his similar experience in the UK, Steve Barker was appointed as the group convenor challenged with steering the team to achieve the set objectives.
"At the inaugural meeting in London, last September, the priorities were set to concentrate on cage induction motors designed for VSD operation operating at less than 1000 Volts."
Mr Barker explains.
" The aim of the team is clarify the key points of consideration and the outcome of this working group's activity, WG26, will hopefully be new guidelines to address our core issues."
The core issues are: Additional motor insulation stress due to inverter operation Increases and effects on motor losses (efficency) Oscillating transient motor torques Increased stray motor Bearing currents Electro-magnetically excited motor audible noise.
Under some unfavourable conditions, the above can cause problems or unnecessary irritation to the user and all these points require further investigation.
The remit of IEC's WG26 is to characterise each of these issues in detail, identify possible solutions and finally to suggest design changes where appropriate.
It is hoped that new international guidelines or standards will be in place by within two years, although Mr Barker admits that this is a tough task.
His objective is to provide authoritative information which will assist users to apply equipment correctly and will persuade manufacturers to improve designs where needed.
In the UK study, GAMBICA and REMA evaluated the situation where the quality motors offered by REMA members were controlled by PWM inverters from the GAMBICA suppliers.
Although motor insulation stress is increased with VSD operation (dependent on cable length), the key findings of the team were:- Motors running on a supply voltage of 500V or less are not affected by these stresses Enhanced winding insulation systems are required for supply voltages over 500V A key challenge for the team was to ensure that the guidance was clear and straightforward.
As presented in their technical guide, they point to the need for users of motors running above 500V to pay special attention to the way the motor winding insulation has been constructed.
It is recommended that for supply voltages between 500V and 690V, motors are chosen, from the range offered by REMA members, with an enhanced insulation system.
These readily available motors may cost between 10 and 20 per cent more than a standard design, but they offer the required assurance against costly failures.
If a motor is being considered from alternative suppliers, it is important, say the working group, to establish the pulse withstand capability by discussing the application with the supplier.
These can then be compared to the benchmark pulse withstand characteristics which are included as part of the technical guide.
However, in some cases, for example where a drive is being retro-fitted to an existing motor, or the characteristics of the motor cannot be identified, these recommendations cannot be followed.
In these cases, alternative solutions such as output filters are available and it is usually advisable to consult with the drive and/or motor manufacturer.
Beware, some special cases merit further attention.
For example, drives that use alternative non PWM control strategies (such as direct torque injection schemes), could actually further double the motor's peak voltage stress and therefore special mitigation measures may be needed.
The guide also offers advice on other applications such as active front end drives where further limitations apply.
Finally, the working group points out that it is especially important to note that the use of inverter drives with "Ex" rated motors used in hazardous environments may invalidate the hazardous area certification and the application must be referred to the equipment supplier Mr Barker feels that it is more important than ever to consider the motor and drive as an integral package.
"The persuasive benefits offered by frequency converters will ensure that the expansion of inverter control continues as VSD technology develops.
As industry demands ever more precision and power, at reduce cost of purchase and operation, so motor and drive producers are striving to build components and sub systems that deliver the expected performance.
While the connection between motor and inverter supply is usually straightforward, there are still a number of issues which need to be carefully considered.
Whilst the vast majority of VSD driven motors are applied without issue, some special cases require additional guidance.
To date, little independent advice on handling such issues has been available.
Some information on the motor is available from the technical report IEC34 -17 1998 "Guide for the application of cage induction motors fed from converters", but this does not reflect current state of the art and is inadequate for modern inverters.
A little further guidance on VSD issues may be obtained from BS EN 61800-2 " Adjustable speed electrical power drive systems - Part 2: General requirements".
Users may therefore feel that an important area has lacked clear guidance so far.
Considerable work relating to the characterisation and specification of cage induction motors and variable frequency converter supplies is being pioneered here in the UK, by a joint working group comprised of industry experts.
Both GAMBICA, the Association for the Instrumentation, Control and Automation Industry, and REMA, the Rotating Electrical Machines Association, have been working on standards and guidelines relating to motors and variable speed drives (VSD).
However, although both associations were working independently towards the same ultimate objective, it fell to Steve Barker (product marketing manager for variable speed drives) at Siemens Automation and Drives in Manchester, to suggest that they teamed up and formed a joint technical committee.
Mr Barker, who is Chair of the GAMBICA Association's VSD Group, explains: "Although it seemed obvious that GAMBICA and REMA should pool their expertise, the idea did appear to be somewhat revolutionary at the time it was suggested."
The concept was enthusiastically embraced by the manufacturers and a taskforce (also convened by Steve Barker) was commissioned to investigate the issue of motor insulation under inverter operation.
The results of the groups joint efforts can already be seen, with the publication of their first Technical Guide, entitled: "Variable Speed Drives and Motors: Motor Insulation and PWM Inverter Drives".
The guide, which is the forerunner to a much more detailed technical report (also now available) on the subject, is one of a series of planned publications that will provide OEM equipment designers, systems integrators and end users with help on the correct selection and use of motor/drive systems.
The co-operation between GAMBICA and REMA has not gone unnoticed internationally.
Through the various international connections of both REMA and GAMBICA, the IEC (International Electrotechnical Commission), who are responsible for setting so many of the product standards now found in factory automation and process control, have also taken up the challenge.
Previously, one IEC committee concerned itself with motors another group concentrated on drives and power electronics.
Impressed with what they saw happening in the UK, the two IEC committees took the decision to create a joint working group to address the specific issues applicable to motors designed to be operated from inverter supplies.
The working group consists of nearly twenty international experts active in the field of both drives and motors.
Together with end users, most of the major manufacturers are represented with delegates from across Europe, North America and Japan.
Based on his similar experience in the UK, Steve Barker was appointed as the group convenor challenged with steering the team to achieve the set objectives.
"At the inaugural meeting in London, last September, the priorities were set to concentrate on cage induction motors designed for VSD operation operating at less than 1000 Volts."
Mr Barker explains.
" The aim of the team is clarify the key points of consideration and the outcome of this working group's activity, WG26, will hopefully be new guidelines to address our core issues."
The core issues are: Additional motor insulation stress due to inverter operation Increases and effects on motor losses (efficency) Oscillating transient motor torques Increased stray motor Bearing currents Electro-magnetically excited motor audible noise.
Under some unfavourable conditions, the above can cause problems or unnecessary irritation to the user and all these points require further investigation.
The remit of IEC's WG26 is to characterise each of these issues in detail, identify possible solutions and finally to suggest design changes where appropriate.
It is hoped that new international guidelines or standards will be in place by within two years, although Mr Barker admits that this is a tough task.
His objective is to provide authoritative information which will assist users to apply equipment correctly and will persuade manufacturers to improve designs where needed.
In the UK study, GAMBICA and REMA evaluated the situation where the quality motors offered by REMA members were controlled by PWM inverters from the GAMBICA suppliers.
Although motor insulation stress is increased with VSD operation (dependent on cable length), the key findings of the team were:- Motors running on a supply voltage of 500V or less are not affected by these stresses Enhanced winding insulation systems are required for supply voltages over 500V A key challenge for the team was to ensure that the guidance was clear and straightforward.
As presented in their technical guide, they point to the need for users of motors running above 500V to pay special attention to the way the motor winding insulation has been constructed.
It is recommended that for supply voltages between 500V and 690V, motors are chosen, from the range offered by REMA members, with an enhanced insulation system.
These readily available motors may cost between 10 and 20 per cent more than a standard design, but they offer the required assurance against costly failures.
If a motor is being considered from alternative suppliers, it is important, say the working group, to establish the pulse withstand capability by discussing the application with the supplier.
These can then be compared to the benchmark pulse withstand characteristics which are included as part of the technical guide.
However, in some cases, for example where a drive is being retro-fitted to an existing motor, or the characteristics of the motor cannot be identified, these recommendations cannot be followed.
In these cases, alternative solutions such as output filters are available and it is usually advisable to consult with the drive and/or motor manufacturer.
Beware, some special cases merit further attention.
For example, drives that use alternative non PWM control strategies (such as direct torque injection schemes), could actually further double the motor's peak voltage stress and therefore special mitigation measures may be needed.
The guide also offers advice on other applications such as active front end drives where further limitations apply.
Finally, the working group points out that it is especially important to note that the use of inverter drives with "Ex" rated motors used in hazardous environments may invalidate the hazardous area certification and the application must be referred to the equipment supplier Mr Barker feels that it is more important than ever to consider the motor and drive as an integral package.
"The persuasive benefits offered by frequency converters will ensure that the expansion of inverter control continues as VSD technology develops.
High performance drives and motors from 30-750W
Lenze has extended its range of Panasonic drives and motors with the introduction of the Hyper range. The new range offers a high performance option for power outputs between 30 and 750W, with the benefit that machinery will run faster and with greater accuracy. Ideally suited to synchronised applications such as checkweighers, the Panasonic Hyper products are available as brushless geared motors and low inertia servo style motors.
The Hyper-G is a high performance geared motor with four power output between 30 and 130W, featuring efficient helical gearheads rated for constant torque up to 29Nm and extremely accurate speed holding.
The design is remarkably compact, for example, the 130W motor is only 76mm long.
Both motors and gearheads are enclosed to IP65 and rated at 10,000 hours operating life.
The compact yet dynamic Hyper-Minas is the servo variant, a range of low rotor inertia motors with IP65 enclosure at 100, 200, 400 and 750W.
Each is constructed using brushless technology, with a permanent magnet rotor featuring 8 magnetic poles and Hall effect devices that sense the rotary position.
The Hyper-Minas range of motors can also be combined with planetary gearheads.
Drives from the Hyper range are suitable for use with both geared motors and servo motors.
Supply is 230V single phase, with options at 100V and 24V (for 30 and 50W motors).
The small drive size includes a detachable keypad, up to 16 jog speeds, selectable chopping frequency and 1-24 pulse output/revolution.
The Hyper-G is a high performance geared motor with four power output between 30 and 130W, featuring efficient helical gearheads rated for constant torque up to 29Nm and extremely accurate speed holding.
The design is remarkably compact, for example, the 130W motor is only 76mm long.
Both motors and gearheads are enclosed to IP65 and rated at 10,000 hours operating life.
The compact yet dynamic Hyper-Minas is the servo variant, a range of low rotor inertia motors with IP65 enclosure at 100, 200, 400 and 750W.
Each is constructed using brushless technology, with a permanent magnet rotor featuring 8 magnetic poles and Hall effect devices that sense the rotary position.
The Hyper-Minas range of motors can also be combined with planetary gearheads.
Drives from the Hyper range are suitable for use with both geared motors and servo motors.
Supply is 230V single phase, with options at 100V and 24V (for 30 and 50W motors).
The small drive size includes a detachable keypad, up to 16 jog speeds, selectable chopping frequency and 1-24 pulse output/revolution.
"Servo Motors"...
We see from your search that you're looking for information on the term "Servo Motors", and we have a large number of manufacturers' news releases and technical articles here on Manufacturingtalk which will be of interest. Let me be your guide.
Start with the news release Integrated motion/control offer advantages from Aerotech, which we summarised at the time by saying "Motion and machine control systems offer advantages for automated packaging and processing machine applications, providing fully integrated, single sourced systems.". The same day, we featured the news release CNC router boosts gun stock output 200-300% from Techno: "Replacing a manual pantograph machine with a 4-axis CNC router has increased production of wooden gun stocks by 200-300% to carve out inlets and other areas in the gun stocks.".
In September 2006, we covered the news from Lenze concerning its Synchronous and asynchronous geared motors - take a look at Five more servo geared motors added to range which says: "Servo motors are integrated into the gearboxes with long-life shaft seals and the first pinion on the motor shaft to eliminate a flexible coupling and provide a shorter and more economic assembly.".
Take a look also at the news release from Unison, All-electric tube bender suits small batches, as well as Router cuts development from 2 months to 2 days from Techno, and CNC router boosts gun case production by 400% from Techno.
Start with the news release Integrated motion/control offer advantages from Aerotech, which we summarised at the time by saying "Motion and machine control systems offer advantages for automated packaging and processing machine applications, providing fully integrated, single sourced systems.". The same day, we featured the news release CNC router boosts gun stock output 200-300% from Techno: "Replacing a manual pantograph machine with a 4-axis CNC router has increased production of wooden gun stocks by 200-300% to carve out inlets and other areas in the gun stocks.".
In September 2006, we covered the news from Lenze concerning its Synchronous and asynchronous geared motors - take a look at Five more servo geared motors added to range which says: "Servo motors are integrated into the gearboxes with long-life shaft seals and the first pinion on the motor shaft to eliminate a flexible coupling and provide a shorter and more economic assembly.".
Take a look also at the news release from Unison, All-electric tube bender suits small batches, as well as Router cuts development from 2 months to 2 days from Techno, and CNC router boosts gun case production by 400% from Techno.
Friday, September 29, 2006
"Variable Speed Drives"...
We see from your search that you're looking for information on the term "Variable Speed Drives", and we have a large number of manufacturers' news releases and technical articles here on Engineeringtalk which will be of interest. Let me be your guide.
Start with the news release Find your bearings from SKF UK, which we summarised at the time by saying "Phil Burge, Marketing Manager for SKF, examines the latest developments in bearing technology and explains how correct specification and sourcing can reduce both component and operating costs.". A couple of weeks before, we featured the news release Motor controllers promise massive savings from Emotron: "Electrical motors account for two thirds of industry's energy consumption, and so great energy savings can be made from more efficient motor control, says Bo Andersson.".
In August 2006, we covered the news from AC Technology International concerning its Lenze smd drives - take a look at Drives optimise food process pumping efficiency which says: "Lenze smd drives have been specified by Seepex pumps for supply with its range of innovative progressive cavity pumps.".
Take a look also at the news release from WEG Electric Motors (UK), Simplified Functionality and Reliability, as well as First medium voltage motor starter hits the road from Schneider Electric, and Digital drives take control of critical tasks from Control Techniques.
Start with the news release Find your bearings from SKF UK, which we summarised at the time by saying "Phil Burge, Marketing Manager for SKF, examines the latest developments in bearing technology and explains how correct specification and sourcing can reduce both component and operating costs.". A couple of weeks before, we featured the news release Motor controllers promise massive savings from Emotron: "Electrical motors account for two thirds of industry's energy consumption, and so great energy savings can be made from more efficient motor control, says Bo Andersson.".
In August 2006, we covered the news from AC Technology International concerning its Lenze smd drives - take a look at Drives optimise food process pumping efficiency which says: "Lenze smd drives have been specified by Seepex pumps for supply with its range of innovative progressive cavity pumps.".
Take a look also at the news release from WEG Electric Motors (UK), Simplified Functionality and Reliability, as well as First medium voltage motor starter hits the road from Schneider Electric, and Digital drives take control of critical tasks from Control Techniques.
The merits of new-technology large motors
Technical advances give Large Brushless Drive Systems significant advantages over conventional DC or AC induction motors, as Ed Lee describes in this article
Brush DC motors have been the most prominent variable speed technology since the DC motor was invented (1) by Werner Von Siemens in the late 1800s. It revolutionized variable speed control of industrial machines. The AC induction motor came much later in 1924 invented by Nicolas Tesla.
In 1962 two engineers, T.G Wilson and P.H Trickey published a paper (2) in which they described a "brushless DC" motor.
Magnet and power switching device technology prevented this invention from becoming a practical general purpose drive technology until the late 1980s when Powertec Industrial Corporation started manufacturing general purpose brushless systems at prices competitive with brush DC systems.
AC drives were beginning to see widespread use during this time as well, since power bridge technology was allowing inverter drives to make AC induction systems a practical alternative to DC in some applications.
AC inverters did not provide good torque control or smooth speed control, however, and could not be used in many applications.
By 1993, AC inverters developed into "vector" technology that gave the vector inverter the ability to use an AC induction motor to provide independent torque and speed control similar to DC and Brushless DC, but using an AC induction motor.
A war has been raging ever since between the three technologies, a war that has benefited the industrial consumer.
The prices of DC systems has remained at 1980 levels in spite of inflation while the price of brushless and AC vector systems has dropped to the point that all three technologies are close to the same pricing (with exceptions being at the size extremes).
Brush DC systems have reached the pinnacle of their design, with better motors, brushes, frame configurations, and drives with software control providing the best possible performance and reliability.
AC induction motor systems have advanced to solving most of the standard induction motor problems running on the most modern AC vector drive designs with high speed IGBTs (Insulated Gate Bipolar Transistors) and advanced control algorithms.
Brushless drive systems have also gained ground with better magnets and much improved drive controls (3).
Today's brushless drive systems include motors made with the robust 3rd generation Neodymium-Iron-Boron magnet materials that have much better thermal characteristics and high magnetic strength.
With today's corona-resistance magnet wire insulation and these improved magnets and the exceptional performance of a modern brushless drive, the industrial consumer has available a drive system capable of the roughest application that will also provide high accuracy performance at competitive prices.
Applications where brushless drives are being used today include those not typically requiring very high performance drives, but requiring tough, dependable, continuous duty operation.
A significant number of applications on extruders, wire drawers, winders, cranes, cable tensioners, conveyors, pullers, printing presses, roll formers, and other traditional "tough" applications are being done with brushless drives from the major drive system manufacturers.
Why Brushless?
What is the reason machinery manufacturers and users choose brushless over the time-proven DC drive or the now widely accepted vector induction drive/motor systems?
1- Performance: Brushless systems offer the highest available dynamic accuracy of any of the three major types of drive systems.
Dynamic accuracy results in consistent and repeatable machine performance creating less product variation resulting in higher quality product and higher production rates.
Extensive tests were performed on a blow-molding machine of Brush DC versus Brushless and a clear advantage was shown in production performance from the brushless drive system (4).
2 - Size: brushless motors are the smallest available motors for a given power rating.
The small size fits the requirements for smaller machines taking up less plant floor space, and the lighter weight results in lower shipping cost, easier handling, and lighter machine structure to support the motor, which is usually a substantial part of the mass in many machines (3).
3 - Efficiency: The brushless motor is the most efficient motor technology available today for an industrial application.
This means less heat to get out of the machine, less heat into the manufacturing area, and lower power consumption.
Brushless system efficiencies are typically 2 to 3 percentage points higher than induction vector systems and greater than this against brush DC.
3 Formal tests were conducted by Ontario Hydro (Canada) in a before/after comparison of a machine conversion from brush DC to Brushless DC, in which efficiency improved 13% minimum, and a whopping 78% at 25% speed (7).
4 - Bearing Stress: Unlike AC induction motors 6, particularly large motors 50 or more hp, brushless motors with surface-mounted magnets have very large air gaps and therefore very low stator-rotor capacitive currents.
Large AC motors have substantial difficulty (5) with bearing damage due to current flow from the rotor through the bearing.
Additionally, both brush DC and AC induction motors create very high heat levels in the rotor and much of this heat must be conducted through the shaft and bearings to the stator before being removed by the ambient air.
Brushless motors produce very little rotor heating because there is no electrical current (other than minor eddy-current loss) and no slip in the permanent magnet rotor.
Advancements in magnet technology (reducing cost of magnets), combined with smaller physical size, results in today's brushless motors being less costly to make.
The proliferation of PWM type drives and improvements in manufacturing procedures and economies of scale has created a high performance drive control that costs much less to make than in years past.
This means brushless systems do not necessarily cost more.
In fact, brushless systems may even be less costly that either of the other two primary variable-speed drive technologies in the 20 to 200 hp range.
Brush DC drives still have the cost advantage in the above-200 hp range due to the simple elegance of the controller using SCRs rather than the more costly IGBTs used by both induction vector and brushless.
Motors smaller than 20 hp are made in very high volumes and the induction vector systems, as well as brush DC have the cost advantage in those smaller sizes, where the smaller brushless motor is not enough smaller to make up for the magnet cost.
Who makes large brushless drives today?
Any induction vector drive has the basic power system to run a brushless motor, but brushless motors must be shaft-position commutated and require a different control algorithm (software) than the induction motor.
It is relatively easy to make a standard vector drive run a brushless motor by having a menu choice that selects this different algorithm.
With most manufacturers, their standard drive will run brushless as a menu choice, or EPROM change.
Therefore, virtually all major drive manufacturers make drives today that run PM brushless motors and unlike 10 years ago, there are several manufacturers of large PM brushless motors to choose from.
Summary: Given that efficiency, size, and low maintenance are key issues in drive system selection, brushless motors and drives have enjoyed a growth of use in heretofore "standard" applications where performance at all costs has not been an issue.
California's energy woes will spread to other areas in time.
The nation's energy costs will continue to rise, stressing all parts of our economy and that stress will continue to push high efficiency ASD systems to the front.
References (1) Siemens Corporate Brochure (2) T.G.
Wilson, P.H.
Trickey, "DC Machine with Solid State Commutation", AIEE paper # CP62-1372, Oct 7, 1962 (3) Dan Jones "Very Large Brushless DC Motors in Industrial Applications", Incremotion Associates, Thousand Oaks, CA (4) Test results, Owens-Brockway Corp, results available from Powertec Industrial Motors, Fax 803-328-1870 (5) Thomas Lipo, Donald Novotny, "Circulating Type Motor Bearing Current in Inverter Drives", IEEE Journal # 0-7803-3544 9/96, Sep 1996 (6) Richard Nailen, P.E., "Are ASDs More Trouble Than They're Worth?", Electrical Apparatus, November 1996 (7) Power Study commissioned by Ontario Hydro to third party testing lab, Ortech International Energy Technologies, 1994.
Copies available from Powertec Industrial Motors Fax 803-329-1870 About the author: Edward Lee earned a BSEE from NC State University in 1995 and has worked in all areas of the adjustable speed drive business.
He has designed brush DC and AC induction drives and assisted in the design of brushless DC drives.
Mr.Lee has published several papers on the subject of brushless system design and application.
He is currently employed as General Manager and VP Sales of Powertec Industrial Motors in Rock Hill SC, which makes brushless motors and drives 1/2 to 400 hp.
Brush DC motors have been the most prominent variable speed technology since the DC motor was invented (1) by Werner Von Siemens in the late 1800s. It revolutionized variable speed control of industrial machines. The AC induction motor came much later in 1924 invented by Nicolas Tesla.
In 1962 two engineers, T.G Wilson and P.H Trickey published a paper (2) in which they described a "brushless DC" motor.
Magnet and power switching device technology prevented this invention from becoming a practical general purpose drive technology until the late 1980s when Powertec Industrial Corporation started manufacturing general purpose brushless systems at prices competitive with brush DC systems.
AC drives were beginning to see widespread use during this time as well, since power bridge technology was allowing inverter drives to make AC induction systems a practical alternative to DC in some applications.
AC inverters did not provide good torque control or smooth speed control, however, and could not be used in many applications.
By 1993, AC inverters developed into "vector" technology that gave the vector inverter the ability to use an AC induction motor to provide independent torque and speed control similar to DC and Brushless DC, but using an AC induction motor.
A war has been raging ever since between the three technologies, a war that has benefited the industrial consumer.
The prices of DC systems has remained at 1980 levels in spite of inflation while the price of brushless and AC vector systems has dropped to the point that all three technologies are close to the same pricing (with exceptions being at the size extremes).
Brush DC systems have reached the pinnacle of their design, with better motors, brushes, frame configurations, and drives with software control providing the best possible performance and reliability.
AC induction motor systems have advanced to solving most of the standard induction motor problems running on the most modern AC vector drive designs with high speed IGBTs (Insulated Gate Bipolar Transistors) and advanced control algorithms.
Brushless drive systems have also gained ground with better magnets and much improved drive controls (3).
Today's brushless drive systems include motors made with the robust 3rd generation Neodymium-Iron-Boron magnet materials that have much better thermal characteristics and high magnetic strength.
With today's corona-resistance magnet wire insulation and these improved magnets and the exceptional performance of a modern brushless drive, the industrial consumer has available a drive system capable of the roughest application that will also provide high accuracy performance at competitive prices.
Applications where brushless drives are being used today include those not typically requiring very high performance drives, but requiring tough, dependable, continuous duty operation.
A significant number of applications on extruders, wire drawers, winders, cranes, cable tensioners, conveyors, pullers, printing presses, roll formers, and other traditional "tough" applications are being done with brushless drives from the major drive system manufacturers.
Why Brushless?
What is the reason machinery manufacturers and users choose brushless over the time-proven DC drive or the now widely accepted vector induction drive/motor systems?
1- Performance: Brushless systems offer the highest available dynamic accuracy of any of the three major types of drive systems.
Dynamic accuracy results in consistent and repeatable machine performance creating less product variation resulting in higher quality product and higher production rates.
Extensive tests were performed on a blow-molding machine of Brush DC versus Brushless and a clear advantage was shown in production performance from the brushless drive system (4).
2 - Size: brushless motors are the smallest available motors for a given power rating.
The small size fits the requirements for smaller machines taking up less plant floor space, and the lighter weight results in lower shipping cost, easier handling, and lighter machine structure to support the motor, which is usually a substantial part of the mass in many machines (3).
3 - Efficiency: The brushless motor is the most efficient motor technology available today for an industrial application.
This means less heat to get out of the machine, less heat into the manufacturing area, and lower power consumption.
Brushless system efficiencies are typically 2 to 3 percentage points higher than induction vector systems and greater than this against brush DC.
3 Formal tests were conducted by Ontario Hydro (Canada) in a before/after comparison of a machine conversion from brush DC to Brushless DC, in which efficiency improved 13% minimum, and a whopping 78% at 25% speed (7).
4 - Bearing Stress: Unlike AC induction motors 6, particularly large motors 50 or more hp, brushless motors with surface-mounted magnets have very large air gaps and therefore very low stator-rotor capacitive currents.
Large AC motors have substantial difficulty (5) with bearing damage due to current flow from the rotor through the bearing.
Additionally, both brush DC and AC induction motors create very high heat levels in the rotor and much of this heat must be conducted through the shaft and bearings to the stator before being removed by the ambient air.
Brushless motors produce very little rotor heating because there is no electrical current (other than minor eddy-current loss) and no slip in the permanent magnet rotor.
Advancements in magnet technology (reducing cost of magnets), combined with smaller physical size, results in today's brushless motors being less costly to make.
The proliferation of PWM type drives and improvements in manufacturing procedures and economies of scale has created a high performance drive control that costs much less to make than in years past.
This means brushless systems do not necessarily cost more.
In fact, brushless systems may even be less costly that either of the other two primary variable-speed drive technologies in the 20 to 200 hp range.
Brush DC drives still have the cost advantage in the above-200 hp range due to the simple elegance of the controller using SCRs rather than the more costly IGBTs used by both induction vector and brushless.
Motors smaller than 20 hp are made in very high volumes and the induction vector systems, as well as brush DC have the cost advantage in those smaller sizes, where the smaller brushless motor is not enough smaller to make up for the magnet cost.
Who makes large brushless drives today?
Any induction vector drive has the basic power system to run a brushless motor, but brushless motors must be shaft-position commutated and require a different control algorithm (software) than the induction motor.
It is relatively easy to make a standard vector drive run a brushless motor by having a menu choice that selects this different algorithm.
With most manufacturers, their standard drive will run brushless as a menu choice, or EPROM change.
Therefore, virtually all major drive manufacturers make drives today that run PM brushless motors and unlike 10 years ago, there are several manufacturers of large PM brushless motors to choose from.
Summary: Given that efficiency, size, and low maintenance are key issues in drive system selection, brushless motors and drives have enjoyed a growth of use in heretofore "standard" applications where performance at all costs has not been an issue.
California's energy woes will spread to other areas in time.
The nation's energy costs will continue to rise, stressing all parts of our economy and that stress will continue to push high efficiency ASD systems to the front.
References (1) Siemens Corporate Brochure (2) T.G.
Wilson, P.H.
Trickey, "DC Machine with Solid State Commutation", AIEE paper # CP62-1372, Oct 7, 1962 (3) Dan Jones "Very Large Brushless DC Motors in Industrial Applications", Incremotion Associates, Thousand Oaks, CA (4) Test results, Owens-Brockway Corp, results available from Powertec Industrial Motors, Fax 803-328-1870 (5) Thomas Lipo, Donald Novotny, "Circulating Type Motor Bearing Current in Inverter Drives", IEEE Journal # 0-7803-3544 9/96, Sep 1996 (6) Richard Nailen, P.E., "Are ASDs More Trouble Than They're Worth?", Electrical Apparatus, November 1996 (7) Power Study commissioned by Ontario Hydro to third party testing lab, Ortech International Energy Technologies, 1994.
Copies available from Powertec Industrial Motors Fax 803-329-1870 About the author: Edward Lee earned a BSEE from NC State University in 1995 and has worked in all areas of the adjustable speed drive business.
He has designed brush DC and AC induction drives and assisted in the design of brushless DC drives.
Mr.Lee has published several papers on the subject of brushless system design and application.
He is currently employed as General Manager and VP Sales of Powertec Industrial Motors in Rock Hill SC, which makes brushless motors and drives 1/2 to 400 hp.
Debut at Drives and Controls
AEG Lafert Electric Motors will be exhibiting its range of induction motors for the first time at the Drives and Controls Show at the UK NEC.
AEG Lafert Electric Motors will be exhibiting its range of induction motors for the first time at the Drives and Controls Show at the UK NEC. The venue heralds the launch of the AM integrated range that has been developed in the powers 0.09-200kW following a GBP 1.1 million investment programme by the Lafert Group. The first principle in the design of the AM is to provide flexibility for the machine builder while enhancing its reputation for end-user reliability.
Mechanical variations of shaft and flanges allow choice for the machine builder to include the AM Motor in the most difficult and exacting space envelopes.
Examples of customer-engineered products will be displayed on stand D7 AEG Lafert will also offer lower running costs for the end-user with its range of CEMEP class Eff1 motors available in a complete range from 1.1-90kW and eligible for Enhanced Capital Allowances under the DEFRA and Inland revenue scheme New for the show will be the recently TUM approved Vulcano range of fire and smoke ventilation motors, suitable for duties of up to 4000C for 2h in emergency use these motors provide protection in public buildings when used within a ventilation system.
Other special application motors to be shown are the new range of AM type single phase and Brake motors.
A new area for AEG Lafert is the brushless servo and drives market where distributors are currently being recruited.
Nigel Evenett Managing Director, states: "This show is an opportunity for us to display in shop window style all that AEG Electric Motors can offer to the UK market.
Much of it is new product, but we bring with it some fresh ideas as well".
AEG Lafert Electric Motors will be exhibiting its range of induction motors for the first time at the Drives and Controls Show at the UK NEC. The venue heralds the launch of the AM integrated range that has been developed in the powers 0.09-200kW following a GBP 1.1 million investment programme by the Lafert Group. The first principle in the design of the AM is to provide flexibility for the machine builder while enhancing its reputation for end-user reliability.
Mechanical variations of shaft and flanges allow choice for the machine builder to include the AM Motor in the most difficult and exacting space envelopes.
Examples of customer-engineered products will be displayed on stand D7 AEG Lafert will also offer lower running costs for the end-user with its range of CEMEP class Eff1 motors available in a complete range from 1.1-90kW and eligible for Enhanced Capital Allowances under the DEFRA and Inland revenue scheme New for the show will be the recently TUM approved Vulcano range of fire and smoke ventilation motors, suitable for duties of up to 4000C for 2h in emergency use these motors provide protection in public buildings when used within a ventilation system.
Other special application motors to be shown are the new range of AM type single phase and Brake motors.
A new area for AEG Lafert is the brushless servo and drives market where distributors are currently being recruited.
Nigel Evenett Managing Director, states: "This show is an opportunity for us to display in shop window style all that AEG Electric Motors can offer to the UK market.
Much of it is new product, but we bring with it some fresh ideas as well".
Thursday, September 28, 2006
ABB mean to capture 20% of LV AC drives market
ABB is on course to capture 20% of the UK market for low voltage AC drives in 2005, according to Steve Ruddell, head of the company's UK drives and motors division.
ABB is on course to capture 20% of the UK market for low voltage AC drives in 2005, according to Steve Ruddell, head of the company's UK drives and motors division. Ruddell, who took control of the drives business a year ago, to add to his responsibilities for motors, was charged at the time of his appointment with growing both businesses at the rate of 10% a year. Much of ABB's expansion in the AC drives market is due to its success in HVAC, where the company is making great strides with a tailor-made product for this industry and a newly established network of distributors.
Together with smaller increases in other market segments, this has led to a 67% increase in factory output of drives up to 110kW over the past year.
In the motors market, ABB is selling on a quality message, highlighting to customers that high quality motors cost far less than their low cost counterparts over the course of the life cycle.
The strategy here is not to become drawn into a price war: 'The struggle for market share going on in the UK LV motors market right now has brought price levels that are unsustainable,' Ruddell says.
Ruddell believes the current price war in the motors market will backfire and that the losers will be end users who opted for cheap motors which will ultimately prove to be an expensive choice.
The increasing prices of copper and steel mean that some manufacturers selling motors at rock bottom prices are barely covering their production costs.
'If a motor manufacturer goes under because it has been selling too cheaply, its OEM customers are faced with increased costs,' says Ruddell.
'They will not be able to get motors elsewhere for the same price and so will only be able to fulfill their outstanding orders at a loss'.
'What end-users must realise is that lower quality motors will end up costing them money - in wasted energy, in downtime and the cost of replacement when those cheap motors fail.' ABB is also trying to spread the energy-saving benefits of efficient motors and drives by telling financial directors of the advantages they can bring.
'Financial Directors are often reluctant to fund energy saving schemes, yet with the cost of electricity climbing by as much as 30% a year, cutting the energy bill is becoming a highly profitable option.' Ruddell believes there is still much scope for growth in the drives market, with many potential customers still to be converted to the major benefits that variable speed drives and energy efficient motors can being to a business. Request free introductory details about products from ABB Automation Technologies (Drives and Motors)....
ABB is on course to capture 20% of the UK market for low voltage AC drives in 2005, according to Steve Ruddell, head of the company's UK drives and motors division. Ruddell, who took control of the drives business a year ago, to add to his responsibilities for motors, was charged at the time of his appointment with growing both businesses at the rate of 10% a year. Much of ABB's expansion in the AC drives market is due to its success in HVAC, where the company is making great strides with a tailor-made product for this industry and a newly established network of distributors.
Together with smaller increases in other market segments, this has led to a 67% increase in factory output of drives up to 110kW over the past year.
In the motors market, ABB is selling on a quality message, highlighting to customers that high quality motors cost far less than their low cost counterparts over the course of the life cycle.
The strategy here is not to become drawn into a price war: 'The struggle for market share going on in the UK LV motors market right now has brought price levels that are unsustainable,' Ruddell says.
Ruddell believes the current price war in the motors market will backfire and that the losers will be end users who opted for cheap motors which will ultimately prove to be an expensive choice.
The increasing prices of copper and steel mean that some manufacturers selling motors at rock bottom prices are barely covering their production costs.
'If a motor manufacturer goes under because it has been selling too cheaply, its OEM customers are faced with increased costs,' says Ruddell.
'They will not be able to get motors elsewhere for the same price and so will only be able to fulfill their outstanding orders at a loss'.
'What end-users must realise is that lower quality motors will end up costing them money - in wasted energy, in downtime and the cost of replacement when those cheap motors fail.' ABB is also trying to spread the energy-saving benefits of efficient motors and drives by telling financial directors of the advantages they can bring.
'Financial Directors are often reluctant to fund energy saving schemes, yet with the cost of electricity climbing by as much as 30% a year, cutting the energy bill is becoming a highly profitable option.' Ruddell believes there is still much scope for growth in the drives market, with many potential customers still to be converted to the major benefits that variable speed drives and energy efficient motors can being to a business. Request free introductory details about products from ABB Automation Technologies (Drives and Motors)....
Literature features air motors and drives
New literature from Motair contains details on all three of the company's ranges of air motors and drives.
New literature from Motair contains details on all three of the company's ranges of air motors and drives: the Rotair rotary lobe, the Globe Vane and the latest addition, the Bulldog compact geared motor. The new literature includes performance tables, features and benefits for all the products. The brochure also details the modular design of the Rotair rotary lobe air motor allowing custom built units, even in small quantity, to be cost effective.
As well as air motors, Motair offers an almost infinite range of geared drives to suit all applications.
New literature from Motair contains details on all three of the company's ranges of air motors and drives: the Rotair rotary lobe, the Globe Vane and the latest addition, the Bulldog compact geared motor. The new literature includes performance tables, features and benefits for all the products. The brochure also details the modular design of the Rotair rotary lobe air motor allowing custom built units, even in small quantity, to be cost effective.
As well as air motors, Motair offers an almost infinite range of geared drives to suit all applications.
Motors and drives for synchrotron
Micromech has recently been awarded a contract to supply motors, drives and other related equipment for Diamond Light Source
Diamond Light Source is a prestigious new synchrotron, currently being built in South Oxfordshire on the Chilton/Harwell science campus. This new science facility could be described as a 'super microscope', housed in a striking doughnut-shaped building over half a kilometre in circumference, and covering an area the size of five football pitches. Diamond will ultimately host more than 30 cutting edge research stations, supporting the life, physical and environmental sciences.
Micromech supplies a wide range of motion control products plus associated equipment to industry and manufacturing.
From a comprehensive range of components to complete motion control packages, Micromech offers a first class before and after technical support service.
At the heart of a synchrotron is its storage ring; a doughnut-shaped vacuum chamber through which electrons hurtle at nearly the speed of light.
As these electrons circle through specially designed magnets arrayed around the ring, they lose energy, which emerges as beams of very bright, highly-focused light of different wavelengths such as X-rays.
It is this light that scientists use to drive their experiments.
The 650m circumference storage ring is made up of 24 segments or cells, comprising magnets, diagnostics and vacuum equipment supported on a system of girders.
These girders are mounted on cams, which will provide highly precise adjustments to the girders' orientation as required by the overall control system.
A few times over the course of the year, the system will be required to make minute adjustments to the storage ring to compensate for movement in the building's foundations.
The storage ring positioning system will use 375 motor gearbox assemblies, with the overall output of the motor-gearbox being in excess of 300Nm to position the ring accurately.
Micromech will additionally supply all necessary cables, drive amplifiers, power supplies and controller cards, which will be assembled and tested at Micromech in racks supplied by Diamond, and then commissioned onsite in the storage ring.
Diamond Light Source is a prestigious new synchrotron, currently being built in South Oxfordshire on the Chilton/Harwell science campus. This new science facility could be described as a 'super microscope', housed in a striking doughnut-shaped building over half a kilometre in circumference, and covering an area the size of five football pitches. Diamond will ultimately host more than 30 cutting edge research stations, supporting the life, physical and environmental sciences.
Micromech supplies a wide range of motion control products plus associated equipment to industry and manufacturing.
From a comprehensive range of components to complete motion control packages, Micromech offers a first class before and after technical support service.
At the heart of a synchrotron is its storage ring; a doughnut-shaped vacuum chamber through which electrons hurtle at nearly the speed of light.
As these electrons circle through specially designed magnets arrayed around the ring, they lose energy, which emerges as beams of very bright, highly-focused light of different wavelengths such as X-rays.
It is this light that scientists use to drive their experiments.
The 650m circumference storage ring is made up of 24 segments or cells, comprising magnets, diagnostics and vacuum equipment supported on a system of girders.
These girders are mounted on cams, which will provide highly precise adjustments to the girders' orientation as required by the overall control system.
A few times over the course of the year, the system will be required to make minute adjustments to the storage ring to compensate for movement in the building's foundations.
The storage ring positioning system will use 375 motor gearbox assemblies, with the overall output of the motor-gearbox being in excess of 300Nm to position the ring accurately.
Micromech will additionally supply all necessary cables, drive amplifiers, power supplies and controller cards, which will be assembled and tested at Micromech in racks supplied by Diamond, and then commissioned onsite in the storage ring.
Wednesday, September 27, 2006
It's cool to match motors with drives
WEG distributor Dorlec has applied a matched WEG 200kW motor/drive package to solve a recurring problem of motor and inverter failures, which was costing thousands of pounds in repair bills and resulting in considerable lost production at SCA Hygiene in Chesterfield. The WEG package gives SCA the benefits of a three-year warranty, which is now standard on all UK supplied WEG drives and motors. SCA is a truly global company, manufacturing some of the most well known brands of absorbent hygiene products in the world.
At the company's Chesterfield mill, paper, for use in tissues and paper towels, is produced in a continuous process, 365 days a year.
The paper is produced on a 50m-long manufacturing line, which includes a large drying cylinder.
Serving this dryer are large wet end and dry end fans, which are crucial to the final stages of the production process.
The wet end fan is controlled by a 200kW inverter/motor combination, which had, until recently, proved to be unreliable, the motor and/or the inverter failing on several occasions, all of which resulted in total line stoppages and considerable lost production.
Faced with this continuing problem, Steve Nam, the engineer in charge of the paper line, enlisted help from WEG distributor Dorlec.
Based locally to SCA in Chesterfield, Dorlec is a specialist in drives and motor control and offers a well-established trouble shooting/fault finding service on drive systems.
Subsequent investigations into the cause of the failures revealed the problem to be a lack of direct short circuit protection against over currents on the main motor output circuit.
In view of this, Dorlec advised replacement of the existing equipment.
SCA agreed, and subsequently a matched 200kW motor/drive package from WEG was installed.
Because of the criticality of the production environment, and the costs of lost production, WEG undertook to back the package from Dorlec with a 3 year warranty - a guarantee which is now offered on all UK supplied WEG motors and drives when provided as packages (motor and drive).
In addition, WEG also undertook to keep a spare drive and motor in stock at Dorlec as an additional backup safeguard for SCA.
Since installation some months ago, the WEG package has performed perfectly under demanding humid conditions, prompting Steve Nam to comment: "No news is good news.
We have worked with Dorlec over many years and they have always come up with the goods.
We like the fact that, with the WEG equipment, we have a the security of a 3-year warranty, a readily available spare, should we require it, and a single source responsibility for the equipment, which is based locally".
The positive results achieved by SCA with the WEG inverter/motor combination directly support those obtained in exhaustive tests carried out at WEG's headquarters in Brazil.
These tests allied WEG's own, and other manufacturers' ranges of drives, with WEG's W21 line of high efficiency motors.
The only variable in the tests was the make of drive, all other conditions being maintained the same The tests revealed that motor temperature increase (delta T) was up to 11% lower using WEG drives, when compared to the other VSDs tested.
This is important for motor longevity, because when motor operating temperature is lower, the benefit is a longer insulation life.
Also aiding motor life is the fact that WEG motors are designed specifically for use with VSDs.
This means that their insulation is not subject to the damage that can arise from rapid voltage rises, this the result of mismatching of motor cable impedance and motor impedance.
However, to protect motors that are not so well insulated, WEG has ensured that the turn on time of the output devices in its new drives is set at a level that reduces voltage rise time.
As this feature is internal to the drive, no additional external output chokes or special output filters are required, ensuring that greater motor reliability is not bought at the expense of additional cost.
At the company's Chesterfield mill, paper, for use in tissues and paper towels, is produced in a continuous process, 365 days a year.
The paper is produced on a 50m-long manufacturing line, which includes a large drying cylinder.
Serving this dryer are large wet end and dry end fans, which are crucial to the final stages of the production process.
The wet end fan is controlled by a 200kW inverter/motor combination, which had, until recently, proved to be unreliable, the motor and/or the inverter failing on several occasions, all of which resulted in total line stoppages and considerable lost production.
Faced with this continuing problem, Steve Nam, the engineer in charge of the paper line, enlisted help from WEG distributor Dorlec.
Based locally to SCA in Chesterfield, Dorlec is a specialist in drives and motor control and offers a well-established trouble shooting/fault finding service on drive systems.
Subsequent investigations into the cause of the failures revealed the problem to be a lack of direct short circuit protection against over currents on the main motor output circuit.
In view of this, Dorlec advised replacement of the existing equipment.
SCA agreed, and subsequently a matched 200kW motor/drive package from WEG was installed.
Because of the criticality of the production environment, and the costs of lost production, WEG undertook to back the package from Dorlec with a 3 year warranty - a guarantee which is now offered on all UK supplied WEG motors and drives when provided as packages (motor and drive).
In addition, WEG also undertook to keep a spare drive and motor in stock at Dorlec as an additional backup safeguard for SCA.
Since installation some months ago, the WEG package has performed perfectly under demanding humid conditions, prompting Steve Nam to comment: "No news is good news.
We have worked with Dorlec over many years and they have always come up with the goods.
We like the fact that, with the WEG equipment, we have a the security of a 3-year warranty, a readily available spare, should we require it, and a single source responsibility for the equipment, which is based locally".
The positive results achieved by SCA with the WEG inverter/motor combination directly support those obtained in exhaustive tests carried out at WEG's headquarters in Brazil.
These tests allied WEG's own, and other manufacturers' ranges of drives, with WEG's W21 line of high efficiency motors.
The only variable in the tests was the make of drive, all other conditions being maintained the same The tests revealed that motor temperature increase (delta T) was up to 11% lower using WEG drives, when compared to the other VSDs tested.
This is important for motor longevity, because when motor operating temperature is lower, the benefit is a longer insulation life.
Also aiding motor life is the fact that WEG motors are designed specifically for use with VSDs.
This means that their insulation is not subject to the damage that can arise from rapid voltage rises, this the result of mismatching of motor cable impedance and motor impedance.
However, to protect motors that are not so well insulated, WEG has ensured that the turn on time of the output devices in its new drives is set at a level that reduces voltage rise time.
As this feature is internal to the drive, no additional external output chokes or special output filters are required, ensuring that greater motor reliability is not bought at the expense of additional cost.
Site covers frameless brushless motors and drives
Motion Control Systems (MCS) has launched a new website with updated information on its range of frameless brushless motors and drives.
Motion Control Systems (MCS) has launched a new website with updated information on its range of frameless brushless motors and drives. The new MCS website www.motioncontrol.org features technical drawings and performance curves for motors ranging from 1.05 to 39.02in O/D. Custom designs are also available, tailor made to suit application requirements.
Using MCS's proprietary magnetic circuits and high-energy magnets, their engineers have created a motor line that combines high power density with smooth, highly reliable performance.
Exceptional efficiency can be achieved to minimise heating and maximise continuous power rating.
By varying the lengths of the lamination and magnetic circuits, a single frame size can handle a wide range of applications.
Details of both the linear and PWM servo amplifiers ranging from 5 to 100kVA are also featured on the new site with the features and performance information for each range included.
Motion Control Systems (MCS) has launched a new website with updated information on its range of frameless brushless motors and drives. The new MCS website www.motioncontrol.org features technical drawings and performance curves for motors ranging from 1.05 to 39.02in O/D. Custom designs are also available, tailor made to suit application requirements.
Using MCS's proprietary magnetic circuits and high-energy magnets, their engineers have created a motor line that combines high power density with smooth, highly reliable performance.
Exceptional efficiency can be achieved to minimise heating and maximise continuous power rating.
By varying the lengths of the lamination and magnetic circuits, a single frame size can handle a wide range of applications.
Details of both the linear and PWM servo amplifiers ranging from 5 to 100kVA are also featured on the new site with the features and performance information for each range included.
Kit helps designers check out motors and drives
Greatly simplifying the startup and evaluation of its small motors, the Vario-Lab kit from ebm-papst Automotive and Drives also evaluates the company's motor drive control systems.
Greatly simplifying the startup and evaluation of its small motors, the Vario-Lab kit from ebm-papst Automotive and Drives also evaluates the company's motor drive control systems. A test and development tool, Vario-Lab kit speeds design time and hence time to market for designers aiming to use ebm-papst motors and control electronics in automotive and other applications. The lab kit is aimed at engineers or indeed any individual who needs to evaluate an ebm-papst motor but does not necessarily possess the knowledge and/or facilities to design and fabricate their own drive/control unit.Contained in a polycarbonate housing measuring just 146 x 91mm, the lab kit enables engineers to rapidly control parameters such as speed and direction of a motor by simply connecting a power supply and the motor to the unit via the terminal blocks supplied.
The unit provides an output voltage range of 12-48V and current levels up to 8A.
Analogue (0-10V) or frequency (PWM) speed commands can be used.
Vario-Lab kit can be used with motors that have their own internal control electronics, alternatively with ebm-papst Automotive and Drives' VT-A and VT-D drive controllers.
A version with a cable harness for use with VT-E can also be supplied on request.
ebmpapst has a heritage of manufacturing high quality motors that fulfil the needs of demanding applications across a broad spectrum of industries.
The company's drive technology embraces motors from 1 to 1500W.
For example, the EC range of motors is proudly hailed by the company as a modern day legend.
In the form of internal or external rotor designs, the robust and reliable EC motors are used in medical technology, in computers, the textile and printing industries as well as in many other sectors.
Tuesday, September 26, 2006
Micromech wins motors and drives contract
Micromech has recently been awarded a contract to supply motors, drives and other related equipment for Diamond Light Source.
Micromech has recently been awarded a contract to supply motors, drives and other related equipment for Diamond Light Source. Diamond Light Source is a prestigious new synchrotron, currently being built in South Oxfordshire on the Chilton/Harwell science campus. This new science facility could be described as a "super microscope", housed in a striking doughnut-shaped building over half a kilometre in circumference, and covering an area the size of five football pitches.Diamond will ultimately host more than 30 cutting edge research stations, supporting the life, physical and environmental sciences.
Micromech supplies a wide range of motion control products plus associated equipment to industry and manufacturing.
From a comprehensive range of components to complete motion control packages, Micromech offers a first class before and after technical support service.
Mr Mackay from Micromech comments: "Since we were established in 1982, we've brought professional distribution techniques to the motion control market".
"In particular, Micromech has become a significant force in the field of sophisticated multi-axis control and is a recognised specialist in servo and stepping motor applications".
"We are delighted to be supplying Diamond Light Source with our high quality equipment".
At the heart of a synchrotron is its storage ring; a doughnut-shaped vacuum chamber through which electrons hurtle at nearly the speed of light.
As these electrons circle through specially designed magnets arrayed around the ring, they lose energy, which emerges as beams of very bright, highly-focused light of different wavelengths such as X-rays.
It is this light that scientists use to drive their experiments.
The 650m circumference storage ring is made up of 24 segments or cells, comprising magnets, diagnostics and vacuum equipment supported on a system of girders.
These girders are mounted on cams, which will provide highly precise adjustments to the girders' orientation as required by the overall control system.
A few times over the course of the year, the system will be required to make minute adjustments to the storage ring to compensate for movement in the building's foundations.
The storage ring positioning system will use 375 motor gearbox assemblies, with the overall output of the motor-gearbox being in excess of 300Nm to position the ring accurately.
Micromech will additionally supply all necessary cables, drive amplifiers, power supplies and controller cards, which will be assembled and tested at Micromech in racks supplied by Diamond, and then commissioned onsite in the storage ring.
Monday, September 25, 2006
Largest catalogue of motors/gears/drives ever?
Maxon Motor UK has completed what is believed to be the largest and most comprehensive catalogue of high precision gears and drives in the world.
Maxon Motor UK has completed what is believed to be the largest and most comprehensive catalogue of high precision gears and drives in the world. The new 228 page publication contains detailed information on more than 57,000 different products. Included for the first time are more than 700 new lines including electric motors, spur and planetary gearheads, electronic and servo-amplifiers.Significantly, it features a fast-growing number of new products exploiting the benefits of ceramics.
According to Keith Ellenden of Maxon Motor UK, "Our new catalogue is one of the most comprehensive guides to high precision drives ever published.
It embraces DC and EC motors in diameters from 6mm to 75mm with assigned power ratings up to 400 Watt.
It also includes maxon motor modular systems with gearheads, DC-tachos, encoders and resolvers.
"The catalogue also comes with a free CD-Rom which not only features all the products contained within the catalogue, but also the maxon selection programme.
This offers the facility to calculate appropriate drive solutions and has the capability to import dimensional drawings (*.dxf) files directly into CAD packages - specifically to help design engineers."
Motors and drives: a practical technology guide
A new book from the Instrumentation, Systems and Automation Society demystifies motor and drive technology used in today's modern manufacturing processes.
A new book from the Instrumentation, Systems, and Automation Society, "Motors and drives: a practical technology guide", demystifies motor and drive technology used in today's modern manufacturing processes. A drive is a device that controls speed, torque, direction, and the resulting horsepower of a motor. There are many drives on the market today.The book compares two drive technologies, AC and DC, and provides questions and issues for manufacturers and engineers to review when making any drive technology decision.
The book introduces engineering concepts of motors and drives in a way that can be easily understood by both engineers and manufacturers unfamiliar with the technology and by technicians who are technically literate but not accustomed to complex theory and mathematics.
"Motors and drives" helps the reader "start from scratch", by gathering and reviewing a collection of basic information, from electrical principles to DC and AC motor principles of operation.
It then provides an overview of drive components and types of drives, with special emphasis given to common motion control applications for DC and AC drive technology.
From the basics, the reader is led on a historical path, reviewing DC and AC drives that are tens years old or more.
The focus of this section, however, points to the new and improved technology in both types of drives.
The reader then learns about feedback methods and devices and drive system control methods.
The book ends with general principles of troubleshooting and ideas on how to conduct routine drive maintenance.
Summary sections and "test your knowledge" questions are provided at the end of each chapter to assist in confirming important points.
Appendices are also offered as a reference section, providing terms and definitions, as well as formulas, conversions, and enclosure information.
"Motors and drives" features simple explanations, summaries, review questions, glossaries, and reference tables.
The text has its roots in the practical side of drive and motor use, with the "design engineering" side of technology presented in commonly used terms.
The author, Dave Polka, makes an overall attempt to start with the basics, and then move into the more complex concepts of drive operation and design.
Design engineers, automation and control specialists, maintenance technicians, and students will find this book to be an invaluable resource, both as a tutorial and as a desk reference.
The author draws on over 20 years of experience as an instructor and developer of technical support and training materials for major drive manufacturing companies.
He has written the book in order that it may be used as a resource for people who design, apply, or maintain AC or DC motor speed controls.
"Motors and drives: a practical technology guide" is available through American Technical Publishers for GBP 70.00.
Brushless DC motors take drives onboard
OEM can now offer Neckar Brushless DC motors with built-in drive electronics which feature velocity or torque mode control.
OEM can now offer Neckar Brushless DC motors with built-in drive electronics which feature velocity or torque mode control. By using either an analogue 0-10V or the integrated potentiometer on the back of the motor, control of the brushless motors is greatly simplified. Applications include small conveyors, winders, packaging machinery and battery powered equipment.Panel space is minimised by having all of the control electronics integrated into the motor.
Sensitive hall sensor wires are kept within the body housing, eliminating the need for complex shielded cable runs.
Other features of the motors include a high power to weight ratio: 36 to 95mm OD at 30 to 250W output powers, plus a speed range of 30:1.
All motors can be combined with spur, worm or planetary gearbox and fully enclosed up top IP65.
Neckar Motors are available exclusively in the UK from OEM Automatic.
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