A photograph taken in the Wardenclyffe plant generator room showing a 200 kilowatt, 3-phase direct-connecting Westinghouse alternating current generator. It was driven by a Westinghouse auto compound engine No.1497, 16 x 27 x 16 feet. The energy of Tesla's steam driven Westinghouse 200 kW alternator was to be channeled instead into an underground structure consisting of iron pipes driven from a point 120 feet beneath the tower's base. This was to be accomplished by combining an extremely low frequency signal (ELF) along with the higher frequency current coursing between the earth and the transmitter's elevated terminal [through the master oscillator and helical resonator]. The low frequency current in the presence of an enveloping corona-induced plasma of free charge carriers would have "pumped" the earth's charge.