Motor-generator - Electrical Power Handling

Electrical Power Handling

In the context of electric power generation and large fixed electrical power systems, a motor-generator consists of an electric motor mechanically coupled to an electric generator (or alternator). The motor runs on the electrical input current while the generator creates the electrical output current, with power flowing between the two machines as a mechanical torque; this provides electrical isolation and some buffering of the power between the two electrical systems. One use of this type of motor-generator is to eliminate spikes and variations in "dirty power" or to provide phase matching between different electrical system; another is to buffer extreme loads on the power system. For example, tokamak fusion devices impose very large peak loads, but relatively low average loads, on the electrical grid. The DIII-D and Princeton Large Torus (PLT) tokamaks and Nimrod synchrotron used a large flywheel on multiple motor-generator rigs to level the load imposed on the electrical system: the motor side slowly accelerated a large flywheel to store energy, which was consumed rapidly during a fusion experiment as the generator side acted as a brake on the flywheel. Similarly, the next generation U.S. Navy aircraft carrier Electromagnetic Aircraft Launch System (EMALS) will use a flywheel motor-generator rig to supply power instantaneously for aircraft launches at greater than the ship's installed generator capacity.