Inverter lockout circuit
OwnerKeith Karl Klett, Robert Philbrick Alleyinventors
Life of this patent
Estimating the term…
Abstract
An emergency lighting system includes a switching transistor inverter circuit for starting and operating a fluorescent lamp from a battery upon failure of line voltage. A lockout arrangement serves to shut down inverter operation should the lamp be removed from its fixture. Included is an interlock in the lamp fixture and circuitry responsive to an open condition at the interlock to ground the input to a system controller inhibit function thereby to effect removal of battery power from the inverter circuit.
Claims16
In a circuit having an inverter including an output for operating at least one gaseous discharge lamp from a DC electrical energy source, the improvement comprising:
- means for shutting down inverter operation including means responsive to placing the output in an unloaded condition by at least partial removal of said at least one gaseous discharge lamp from the circuit when the inverter is operating.
In an inverter circuit for operating a gaseous discharge lamp from a DC electrical energy source, the improvement comprising:
- input means for connection to the DC source;
- output means for connection to the lamp;
- inhibit means having an input connected to the input means for shutting down the inverter circuit when the DC source voltage drops below a predetermined value;
- means for forcing the DC voltage at the input to the inhibit means to drop below the predetermined value when the lamp is at least partially removed from the output means placing the circuit in an unloaded condition whereby inverter circuit turnoff is effected.
In an emergency lighting circuit for operating at least one gaseous discharge lamp including means for connection to an AC electrical energy source for energizing the lamp during normal conditions when the AC source voltage is above a predetermined value and a transistor switching inverter including an output and a DC electrical energy source for energizing the lamp during emergency conditions when the AC source voltage is below the predetermined value, the improvement comprising:
- means for shutting down inverter operation including means responsive to placing the inverter output in an unloaded condition by at least partial removal of said at least one gaseous discharge lamp from the circuit when the inverter is operating.
Dependencies are inferred from the claim text.