Saturday, July 22, 2006
Converging into one industry: Motors controls
Electric motors and electronic motor controls are coming together, to the benefit of the end user.
Industrial electric motors and electronic industrial controls are in the process of merging into one industry, largely due to the urging of many customers for both. Many motor manufacturers now market adjustable speed controls and motion controllers. Others work from the ground up from original designs. Significantly, the leading controls manufacturer has entered the motor field.
The consolidation continues rapidly in North America, and globally as well. We at Baldor Electric and many others believe this is a healthy trend, because it benefits users of both motors and controls. Also, it is definitely to the benefit of designers of systems incorporating motors and controls. One important reason is compatibility: though using components from one manufacturer does not guarantee compatibility, it certainly improves the odds for success.
There is also the important subject of responsibility. A look at the history of these industries will illustrate this.
Electric motors have been important to industry for more than one hundred years, and have become a medium-sized industry of approximately $10 billion dollars per year in North America, and two or three times this large globally.
A second industry, known by many names but which we'll refer to as industrial controls, was born soon after. A large percentage of these controls were designed and used originally to start and stop motors. Then later, in some cases, there were many different ways to adjust the speed of motors, usually direct-current motors. In fact, one of Thomas Edison's reasons for supporting the use of DC motors rather than AC motors was their controllability.
These old controls were mostly electromechanical. Power electronics, including the old thyratrons and other devices, gradually took over some of these applications, sometimes improved their performance, and often lowered costs.
Until 1960, most industrial-motor speed controls were large, heavy, and expensive. An exception was the military use of servos. With the invention of the silicon-controlled rectifier (SCR) in the late 1950s at Bell Labs, the ability to control industrial motors rapidly increased (Figure 1).
Subscribe to Posts [Atom]
