Also called dv/dt reactors, these reactors are used in series between the AC inverter output terminals and the motor. Since the inverter voltage is comprised of impulses at high switching frequency, the insulation of the motor can become stressed. This situation is further exacerbated by motor cable length, due to a phenomenon referred to as voltage reflection which occurs in long cable lengths when the load impedance is higher than the line impedance. Voltage stress in the cable and motor windings is caused by the rapid rise of the voltage impulses as well as the repetitive nature of these impulses. Additionally, the ultimate peak voltage level appearing at the motor terminals increases by the magnitude of the reflected voltage pulses. The fast dv/dt pulses, in combination with the length of the cables, generate electrostatic currents which can destroy the motor winding insulation.

Meher-Mangoldt PWM Load Reactors reduce the dv/dt rate of voltage pulses, increase line impedance and restrict the development of electrostatic stress.