A New Synthetic Loading for Large Induction Machines with No Feedback into the Power System

Full load testing of large induction machines are constrained by the limitations in the power supply and loading equipment of the manufacturer's facilities resulting in costly set-up time. A new synthetic loading method is proposed based on a bang-bang phase control strategy. The rated power oscillation created is routed to an auxiliary system and the source hydra has to provide only the total losses of the system, without seeing the excessive power swings observed in other synthetic loading techniques. In this technique, only induction machines are used, which would enable motor manufacturers to build the test rig in house. The control stage is very simple to implement and requires only unregulated dc supplies for the excitation windings. The method is suitable for any induction machine and requires no set-up time. It is possible to strictly maintain constant RMS voltage and current at rated values for the duration of the heat runs.