Backup power circuit
First Claim
1. A backup power circuit for automatically energizing a multi-power requirement load upon failure of its primary power source comprising:
- a direct current source;
a power loss detection circuit connected to monitor a power parameter of the load, a predetermined change in the power parameter from its normal condition causing the power loss detecting circuit to generate a fault signal;
solid state timer means responsive to the fault signal, the timer means providing a trigger signal a predetermined time period after the generation of the fault signal, the triggering signal continuing for a predetermined time period subsequent to the termination of the fault signal generation by the power loss detection circuit;
solid state inverter means connected to the direct current source and responsive to the trigger signal, the inverter means providing an alternating current output during the generation of the trigger signal by the timer means;
step-up transformer means connected to the alternating current output of the inverter, the transformer means providing alternating current to the load at a voltage exceeding that of the alternating current output of the inverter;
rectifier means connected to the transformer means, the rectifier means providing direct current to the load at a voltage exceeding that of the direct current source; and
relay means responsive to operation of the inverter means, the relay means being actuated generally simultaneously with energization of the inverter means to disconnect from the primary power source those portions of the load energized by the current outputs of the transformer and rectifier means.
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Accused Products
Abstract
A battery pack-containing solid state circuit, normally in a standby condition, automatically applies battery-generated power to a multi-power requirement load a predetermined time period subsequent to detection of a malfunction in the load'"'"'s normal power source. In switching to its power-applying state, the circuit disconnects the load from its malfunctioning power source and energizes the load at a level consistent with the battery pack capabilities. The circuit includes a unique foldback-characterized, overcurrent-protected inverter and a temperature-compensated battery charger. A low battery voltage sensor exhibiting hysteresis characteristics inhibits operation of the circuit when the battery voltage drops below a predetermined level indicative of a discharge condition, the low voltage sensor continuing to inhibit operation of the circuit until a battery voltage charging input regains a level in excess of the predetermined level at which the discharged battery initially inhibited circuit operation. Restoration of normal power resets the circuit to a standby condition after a predetermined time period. The circuit finds particular application as an emergency power unit to effect lowering of an hydraulic elevator car and release of passengers therefrom.
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Citations
9 Claims
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1. A backup power circuit for automatically energizing a multi-power requirement load upon failure of its primary power source comprising:
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a direct current source; a power loss detection circuit connected to monitor a power parameter of the load, a predetermined change in the power parameter from its normal condition causing the power loss detecting circuit to generate a fault signal; solid state timer means responsive to the fault signal, the timer means providing a trigger signal a predetermined time period after the generation of the fault signal, the triggering signal continuing for a predetermined time period subsequent to the termination of the fault signal generation by the power loss detection circuit; solid state inverter means connected to the direct current source and responsive to the trigger signal, the inverter means providing an alternating current output during the generation of the trigger signal by the timer means; step-up transformer means connected to the alternating current output of the inverter, the transformer means providing alternating current to the load at a voltage exceeding that of the alternating current output of the inverter; rectifier means connected to the transformer means, the rectifier means providing direct current to the load at a voltage exceeding that of the direct current source; and relay means responsive to operation of the inverter means, the relay means being actuated generally simultaneously with energization of the inverter means to disconnect from the primary power source those portions of the load energized by the current outputs of the transformer and rectifier means. - View Dependent Claims (2, 3, 4)
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5. A backup power circuit for automatically energizing at least a portion of a multi-power requirement load upon failure of its primary power source comprising:
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a battery; a solid state battery charger having its output connected to the battery to effect charging thereof; a solid state low voltage sensor connected to and in electrical series relationship with the battery, the sensor monitoring the voltage level of the battery, the low voltage sensor having a normal low impedance current passing state and a high impedance current blocking state, the sensor switching to its high impedance current blocking state when the battery voltage drops below a predetermined level; a solid state power loss detection circuit connected to monitor a power parameter of the load, a predetermined change in the power parameter from its normal condition causing the power loss detection circuit to generate a fault signal, the solid state detection circuit being energized by current from the battery conducted via the low voltage sensor in its normal low impedance current passing state, the low voltage sensor being series-inserted between the battery and the detection circuit power input wherein the low voltage sensor at its high impedance state inhibits operation of the detection circuit to preclude generation of the fault signal when the battery voltage is below the predetermined level; solid state timer means responsive to the fault signal, the timer means providing a trigger signal a predetermined time period after the generation of the fault signal; solid state inverter means connected to the battery and responsive to the trigger signal, the inverter providing an alternating current output during the generation of the trigger signal by the timer means; step-up transformer means having a primary side connected to the alternating current output of the inverter and a secondary side, the transformer means secondary side providing alternating current to the load at a voltage exceeding that of the alternating current output of the inverter; rectifier means connected to the transformer means secondary side, the rectifier means providing direct current to the load at a voltage exceeding that of the battery; and relay means responsive to operation of the inverter means, the relay means being actuated generally simultaneously with energization of the inverter means to disconnect from the primary power source those portions of the load energized by the current outputs of the transformer secondary side and the rectifier means. - View Dependent Claims (6, 7, 8, 9)
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Specification