The motor should be located as close to the VFD as possible (100 feet or less). For applications where the motor is to be located more than 100 feet away from the VFD, a load reactor or dV/dt filter should be installed. As motor lead length increases, voltage spikes generated by the VFD’s output transistors become amplified. In extreme cases, these spikes can result in premature insulation breakdown in the motor. Adding an output reactor or dV/dt filter reduces the spikes.
Most LEESON® motors are now using IRIS® inverter rated insulation system. Motors with this feature allow longer motor leads (200-300 feet) without the use of an output reactor or filter.