The present invention relates to accessory equipment for industrial circuit breakers, and particularly to a combined circuit breaker bell alarm and lockout accessory apparatus.
Automatic electric circuit breakers, particularly those of the industrial type, are often equipped with so-called bell alarm switches operating to complete a signal circuit and thus sound an alarm at a remote location to indicate that the circuit breaker has been automatically tripped to interrupt its circuit. Typically, the alarm is for the benefit of maintenance personnel to alert them to the existence of an abnormal circuit condition requiring prompt corrective measures. The bell alarm switch is normally adapted to be actuated only when the circuit breaker is tripped automatically because of an overcurrent condition or an undervoltage condition, and not when the circuit breaker is opened via its manual operating handle or when the breaker is manually tripped.
When the circuit breaker has been tripped automatically, it is important that it not be reclosed until the abnormal circuit condition precipitating the trip function has been corrected. Unauthorized reclosure of the circuit breaker before or during correction of the abnormal condition can produce harmful consequences to equipment and maintenance personnel.
It is accordingly an object of the present invention to provide improved apparatus for automatic industrial circuit breakers in which bell alarm and breaker lockout accessorial functions are structurally integrated.
A further object is to provide a circuit breaker accessory apparatus of the above character which is structured to impose a combined breaker lockout and bell alarm function incident with automatic tripping of the circuit breaker.
An additional object is to provide circuit breaker accessory apparatus of the above character which is structured for convenient cancelling of the bell alarm and breaker lockout function once it has been imposed incident to automatic tripping of the breaker and for automatically inhibiting the bell alarm and lockout function when tripping of the breaker is manually initiated.
Yet another object is to provide circuit breaker accessory apparatus of the above character which is inexpensive to manufacture, reliable in operation and convenient to use.
Other objects of the invention will in part be obvious and in part appear hereinafter.
USPTO Backgrounds
USPTO Backgrounds