START PAC VOLTAGE REDUCTION UNIT 1400-JR VRU

Most aircraft, fixed wing and helicopters, have over voltage protection relays to protect aircraft systems from damage due to high voltages from GPU’s. Unfortunately, there is no industry standard for the setting of these relays but most are 30 to 31 volts. Some GPU’s can range from 28 to 30 volts depending on brand and age. A 28 volt battery pack can actually read over 30 volts when fully charged. When connected between the GPU and the aircraft the VRU will lower the voltage where in many cases will allow the aircraft to accept the GPU.