The function and applications of these handy devices.
VFDs work in conjunction with three-phase alternating current motors. To understand how VFDs work, we first need to know how three-phase motors work.Three-phase electric motors are like dogs chasing a rabbit. You've seen pictures of greyhound dog races where an electric rabbit is on the inside rail leading the dogs around the track, always staying a few feet out in front. A three-phase electric motor works the same. Instead of a rabbit, the three-phase motor has a rotating magnetic field created in the stator, which is the stationary portion of the motor that contains the wire windings. These windings form magnetic poles, and when they are energized by three-phase alternating current, a rotating field is set up much like the rabbit on the inside rail (see Figure 1).