Solid-state ac-power supplies offer a single point source for variable frequencies and voltages used in transformer testing. For example, this Pacific Power Source frequency converter provides up to 62.5 kVA from 40 to 400 Hz at 0 to 120/208 V in a 3 wye or delta power connection. Up to 10 converters may be paralleled for a combined output of 625 kVA.