초록 ▼

A voltage fault detector (10) for producing a trip signal causing switching from a first AC voltage source (12) to a second AC voltage source (14) is disclosed. A plurality of comparators (18,20,22) monitor a signal which is proportional to the magnitude of the voltage of a first AC voltage source (

A voltage fault detector (10) for producing a trip signal causing switching from a first AC voltage source (12) to a second AC voltage source (14) is disclosed. A plurality of comparators (18,20,22) monitor a signal which is proportional to the magnitude of the voltage of a first AC voltage source (12) to determine if sample values fall within predetermined ranges. A counter (30) counts the number of samples falling outside the predetermined range to generate the trip signal when the count reaches a predetermined limit. The counter (30) is augmented for each sample which is outside the predetermined range and decremented for each sample which is within the predetermined range. A plurality of latches (24,26,28) are respectively coupled to a different one of the comparators for applying the output level signal from one of the comparators to the counter at predetermined times under the control of clock signal pulse trains generated by a combinational logic circuit (32) which are respectively applied to a different one of the plurality of latches. The voltage fault detector (10) may be used to monitor the condition of one or more phases of a backup voltage source.

대표청구항 ▼

A voltage fault detector for producing a trip signal causing switching from a first AC voltage source to a second AC voltage source comprising: (a) a plurality of comparators, each comparator producing an output level signal of a first level when a signal, which is proportional to a voltage of the f

A voltage fault detector for producing a trip signal causing switching from a first AC voltage source to a second AC voltage source comprising: (a) a plurality of comparators, each comparator producing an output level signal of a first level when a signal, which is proportional to a voltage of the first AC voltage source, is within a predetermined value and producing the output level signal of a second level when the signal is outside the predetermined range; (b) a plurality of latches, each latch being coupled to the output signal of a different comparator for outputting the output level signal of the comparator to which each latch is coupled in response to a clock signal; (c) means for producing a plurality of clock signal pulse trains, equal in number to the number of comparators, synchronous with the first AC voltage source, a different clock signal pulse train being applied to each of the latches with pulses of each of the clock signal pulse trains being time displaced from the pulses of the other clock signal pulse trains; and (d) counting means, responsive to the plurality of latches for augmenting a count each time an output level signal of the second level is received and decrementing the count each time the output level signal of the first level is received, the trip signal being produced when the counting means reaches a predetermined count indicative of a voltage fault.