Voltage sag ride-through testing of adjustable speed drives using a controllable dynamic dynamometer

Testing of electrical motors and adjustable speed drives during power system voltage sags has become important. The response of the ASD and motor to a sag is shown to be a function of the load type and the inertia of the load, as well as parameters of the drive. A controllable dynamometer is described which can mimic the behavior of actual industrial-type loads during both steady-state and dynamic conditions, with user-selectable characteristics and inertia. The results of testing ASDs and motors with this dynamometer is discussed.