VTdrive Line Reactors and VFDs0 pages

Line reactors can protect motors and reduce power line distortion from VFDs.
Do you have problems with your existing variable-frequency drives (VFDs)? If
so, 3-phase line reactors may be a very viable solution. A line reactor acts not
only as a current-limiting device, but it also filters the waveform and attenuates
electrical noise and transients associated with the system. You can install
reactors in HVAC equipment, pumping equipment, machine tools, elevators,
printing presses, UPS equipment, computer mainframes, robotics equipment,
ski lifts, wind generators, electric cars, cranes, trams, and many other types of
equipment, to extend the service life of the VFD and motor.

Harmonic attenuation. As the name implies, you'd typically use line reactors
on the line side of a VFD, as shown in Fig. 1 at right. Harmonic compensated
line reactors are specially designed to handle the waveform's harmonic content.
By inserting inductive reactance into the circuit, which is a high impedance to
harmonic frequencies, line reactors reduce the amount of harmonics produced
by a VFD system. For harmonic reduction purposes, you typically apply 5%
impedance line reactors to the input of motor drives 20 hp and higher. This
reduces input harmonics to 35% total harmonic current distortion (THID) or less
and minimizes the effects of harmonics on motors and other devices powered
off the same electrical system.
Drive protection.
In situations where you have drives located very close to the incoming facility
power source, such as a substation, they may be susceptible to any incoming
spikes and other transients. This is because there may not be enough
impedance (in the form of transformers, power feeders, and the like) to help
counteract these transient voltage spikes. This situation can damage the front