Series 3PTT Three Phase Auto Testing Transformers allow three phase line voltages to be transformed into various three phase voltages found around the world. Manufacturers, motor rewinders, machinery builders, and automation suppliers will find these versatile autotransformers particularly useful in testing motors and other loads at their rated voltage. Voltages include 208, 220, 240, 380, 440, 480, 550,and 600 volts three phase. All taps are designed to carry full load current at rated voltage. All 3PTT Series transformers are copper wound. All units incorporate a 200C insulation system and a 115C rise for significant overload capacity.