Prior to the advent of the adjustable-speed drive (ASD), the polyphase induction motor operated as a constant-speed motor. Figure 1 shows the well-known torque and current curves versus speed for the ...

Motors are driving demand for electricity, accounting for about half of the electricity we consume, according to the Electric Power Research Institute (EPRI). Many of these motors are found throughout ...

Article 430, Part X provides the NEC requirements for adjustable-speed drive systems. Notice the word “systems,” which means this covers more than the drive itself. Size the branch or feeder circuit ...

The topic of motors and motor control techniques is wide and varied. Part one of this two-part article will cover the principles of alternating-current (AC) motor operation and control. Part two will ...

It is interesting to look at figures from the Energy Information Administration about where energy gets consumed in our economy. These figures reveal that industrial uses account for 31% of all energy ...