A method to limit motor starting current is a series reactor. Iron core or air core reactors can be used for starting purposes. If an air core is used for the series reactor then a very efficient and reliable soft starter can be designed which is more suitable for high MW ratings of synchronous/induction motors at MV levels. The reactors are designed with taps.
Reactor starting always reduces motor accelerating torque. Voltage reduction in the reactor is not fixed, as with an autotransformer, but varies with the current. Since this current is determined by total circuit impedance, motor voltage during acceleration depends upon the relative reactor and motor impedances.
General Options for RVMS Panels
- Instead of incoming vacuum contactor (IVC), a vacuum CB can be used
- If vacuum CB is used, no need to use MV fuses
- Power factor correction capacitors
- Incoming / outgoing surge arresters
- Voltage transformers