DC operated circuit breaker tripping and closing circuit

Simple DC operating wiring for circuit breakers.
  In the figure, YA is the closing coil of the circuit breaker ; YR is the tripping
coil of the circuit breaker; KM is the closing auxiliary contactor, through which the closing coil is activated ( the current passing through the
closing coil is about 50~400A). QF is the auxiliary contact attached to the circuit breaker shaft
; SA is the control switch; ws is the small busbar of the flash power supply.