For Transferring Power Between two Sources
Switches may be configured for open- or closed-transition transfer. For either configuration, if the
primary source is lost, the control initiates an open-transition transfer to the emergency source by tripping the breaker from the primary source and closing the breaker to the emergency source.
For open-transition transfer, once power has been restored, retransfer to normal is accomplished by reversing this process — first tripping the breaker from the emergency source and then closing
the breaker to the primary source.
For closed-transition retransfer to the normal source, the RPTCS control’s power monitoring functions ensure that both sources are within an acceptable window of synchronism before effecting a closed-transition retransfer to the normal source by first closing the normal source breaker and then opening the emergency source breaker.