SWITCHING EQUIPMENT 



553 



be set very high. When operating conditions make it necessary, 

 the overload feature can be very readily disconnected. With 

 motor-driven exciters operating in parallel, it is also advisable to 

 equip the exciter circuits with reverse-current circuit breakers, so 



as to prevent any set which might be disconnected from the bus 

 on the motor side to continue to operate by its exciter running as a 

 motor and taking power from the exciter bus. The D.C. breaker 

 could, of course, also be provided with a shunt trip arrangement 



