Motors & Drives Information

Featuring dual microprocessors and motor control algorithms, Telemecanique[R] Altivar[R] 71 variable speed ac drives handle constant torque applications. Customizable LCD display has navigation wheel that allows users to scroll through menus. Integrated Modbus[R] and CanOpen protocols assure integration into any device level network, and PowerSuite software allows configuration, monitoring, and diagnostics of drives through Ethernet or Bluetooth wireless connection.

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PALATINE, Ill. - SEPTEMBER 6, 2005 - Best-in-class motor control for up to 700 HP motors is now available in the new Telemecanique[R] Altivar[R] 71 variable speed AC drive from Schneider Electric. Dual microprocessors and motor control algorithms provide superior torque performance and speed regulation. Advanced materials reduce the drive's size by 15 percent compared to previous generations. These features make the Altivar 71 the most advanced AC drive on the market for constant torque applications.

Now one of the world's top four manufacturers of variable speed drives and soft starts, Schneider Electric specializes in motor control solutions for industrial and facility applications. The Altivar family of variable speed AC drives provides functionality by incorporating common user interfaces, common I/O options and flexible communication options over the widest horsepower range in the industry.

The operator-friendly design of the Altivar 71 line is evident in a large and easy-to-read, customizable LCD display that uses plain text words and features a navigation wheel that allows users to easily scroll through menus. The new Telemecanique drive family features a common user interface and options, from 0.5 to 700 HP. A quick-start menu incorporates macro-configurations for easy and fast commissioning.

Integrated Modbus[R] and CanOpen protocols assure low-cost integration into any device level network. PowerSuite software that can be used to program all Altivar drives allows configuration, monitoring and diagnostics of the Altivar 71 through an Ethernet or Bluetooth wireless connection. Among the many new features is an integrated oscilloscope function to detect operational drift on machines.

Highly expandable with I/O, communication cards and programmable controller cards, and with more than 150 built-in functions that reduce application costs, the Altivar 71 is ideal for material handling, packaging, hoisting and a wide range of process applications.

A long product life and reliability are assured by protective features at all levels, including advanced thermal protection, an integrated power removable safety function, drive protection and environmental protection in accordance with the WEEE regulations and RoHS standards. The new drive meets IEC, EN, CSA and UL 508C standards. The power removal function has been certified by an independent body for e-stop requirements.

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A new type of AC motor drive has the potential to provide packaging machinery users more precise control for little extra expense.

No-encoder drives use advanced methods of analyzing current and other factors to allow for extra-tight control of speed and torque. They offer the low cost and relatively easy maintenance of AC motors, avoiding the extra expense and fragility of encoder mechanisms.

These motors are not yet used extensively by packaging machinery manufacturers. But as manufacturers strive for more precision and interconnectivity, no-encoder drives are emerging as an alternative and/or supplement to servos, steppers, standard three-phase AC motors and other devices.

"We model the motor itself and from that, based on what the currents are doing, we can tell what speed it's running," says Glenn Frazier, a product manager for Rockwell Automation's drive business. "It's not quite as precise as with an encoder, but it's pretty good."

Controlling the speed and torque of an AC motor depends on several factors. In a sense, speed or torque control is an either/or proposition. A drive can keep the motor's speed at a given rate and vary the torque to stay at that speed; or the torque can stay constant, and the motor will speed up or slow down depending on how much there is to pull. This dichotomy is due to the way AC motors respond to electricity. Speed is a function of the intensity of electric current (expressed as volts), while torque depends on the amount of current (amps).

Both speed and torque control have their place in many kinds of packaging machinery. For instance, in form-fill-seal equipment, speed control is necessary to match the film feed to the packaging flow, says Steve Bergholt, chief engineer for Triangle Package Machinery Co. Torque control is needed to hold and feed the film with just the right amount of tension. A typical form-fill-seal machine will have motors with both torque-based and speed-based drives.

Achieving more precise control has always been a goal of AC motor manufacturers. (In general, AC motors are preferred for industrial machinery. DC motors offer more precise control, especially at low horsepower, but their design makes them harder to maintain.) One increasingly common way to increase speed control for AC motors is through the use of encoders.

An encoder is a device that gives feedback to a drive based on the rotation of the motor or of something it powers. The encoder translates the rotation into analog or digital data. Based on this data, a processor in the drive directs changes to the current being fed to the motor, turning it on or off and altering voltage (to control speed) or amperage (for torque). Many motors, such as servomotors, come with encoders built in. Other encoders are sold on an aftermarket basis, for attachment to the motor's shaft or the driveshaft of a conveyor or other equipment.

Encoders are a well-established technology, especially in servos, whose use in packaging machinery has greatly increased in recent years. Drives that use them, known generically as closed-loop drives, are about 10 times more precise in speed control than open-loop drives.

But encoders have their drawbacks. They add to the cost of the motor, and they're susceptible to accidents and environmental stress.

"The encoder can get knocked off the motor because it was hanging out in an aisle or it was sustaining damage from gases or dust particles--something that would impede its operation," says John Tisdale, a sales manager for ABB Industry Oy.

That's where no-encoder drives can help. No-encoder technology has spawned a new generation of AC drives that can greatly improve a motor's accuracy while maintaining the simple design of a threephase AC induction motor. These drives use an especially sophisticated algorithm in analyzing the current that the motor draws at any given point in its operation.

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