Motor monitoring and protection using residual voltage

Residual voltage measurements taken after removal of electric power to an electric motor are used to improve the functioning of an electric motor monitoring system. For example, an intelligent electronic device (IED) may acquire residual voltage measurements of a motor after disconnected electric power to the motor. The IED may determine a thermal condition of the motor based at least in part on the residual voltage measurement. The IED may prevent starting of the motor based at least in part on the thermal condition.