Reduced Voltage Motor Starting Panels are designed for starting of squirrel cage induction and synchronous motors.
A RVMS Panel reduces the torque by temporarily reducing the voltage and/or current input. It reduces voltage applied to the motor during start up causing lower starting currents from the connected grid.
One way to limit motor starting current is an autotransformer. An auto-transformer is placed in series with the motor during starting. The transformer action reduces the voltage applied to the motor terminals, so the current at starting decreases. They are designed as per the typical voltage taps of 50, 65, 80 percentages of the voltages.