초록 ▼

A circuit for protecting the ac generator and/or load of a diesel-engine generator set is provided. Included is a circuit for measuring indications of the current in each phase of the ac generator, and a switching circuit for protecting the ac generator if the current in any phase is greater than a

A circuit for protecting the ac generator and/or load of a diesel-engine generator set is provided. Included is a circuit for measuring indications of the current in each phase of the ac generator, and a switching circuit for protecting the ac generator if the current in any phase is greater than a predetermined current for a predetermined length of time (overcurrent), or if the current in any phase is less than a predetermined function of the currents in each of the phases for the predetermined length of time (imbalance). The circuit which protects the ac generator preferably short circuits the field winding of the ac generator and thereby turns off the ac generator, and/or closes a fuel valve to effectively turn off the engine should the current imbalance or overcurrent be sensed. In conjunction with the protection circuit, a switch interlock and/or circuit breaker arrangement for shock protection is provided.

대표청구항 ▼

A system for protecting a multiphase ac generator of a diesel-engine generator set to which a load is electrically coupled, the multiphase ac generator having field windings and a plurality of output load carrying conductors carrying current of different phases, said system being coupled to said out

A system for protecting a multiphase ac generator of a diesel-engine generator set to which a load is electrically coupled, the multiphase ac generator having field windings and a plurality of output load carrying conductors carrying current of different phases, said system being coupled to said output load carrying conductors, wherein a fuel valve solenoid is associated with said diesel-engine generator set, said system comprising: a) circuit means coupled to said output load carrying conductors for determining the presence of an undesired overcurrent condition where the current in any of said plurality of output load carrying conductors is greater than a predetermined current for a predetermined length of time, said circuit means including means for providing a signal indicative of an undesired condition in response to a determined undesired overcurrent condition; b) at least one of a means for shorting said field windings and a means for de-energizing said fuel valve solenoid; and c) switch means coupled to said circuit means and coupled to at least one of said means for shorting said field windings and said means for de-energizing said fuel valve solenoid, said switch means for receiving said signal indicative of an undesired condition and for causing said means for shorting to short said field windings and/or for causing said means for de-energizing to de-energize said fuel valve solenoid protecting the ac generator in response to said signal indicative of an undesired condition; and d) switch interlock means coupling said output load carrying conductors to said load, said switch interlock means for preventing an application of voltage from said output load carrying conductors to said load upon initial physical connection of said load to said switch interlock means, and for allowing an application of voltage from said output load carrying conductors to said load upon activation of said switch interlock means, wherein said circuit means comprises a transformer coupling for each of said output load carrying conductors, with the voltage induced in each said transformer coupling being proportional to the current in the respective load carrying conductor, said circuit means further comprises comparator means for comparing voltages related to said voltages induced in each said transformer couplings to predetermined voltages, and for accordingly providing comparator output signals indicative of overcurrent conditions or comparator output signals indicative of permissible current conditions, said comparator means comprises a microprocessor and associated RC circuitry.