Integrity testing of isolation means in an uninterruptible power supply
First Claim
1. An uninterruptible power supply comprising:
- a supply input adapted to be connected to a main power supply;
an output adapted to be connected to an electrical load;
an auxiliary power supply;
a selective isolation means connected between said supply input and said auxiliary power supply for isolating said auxiliary power supply from said supply input during an emergency operation;
a first means establishing a reverse polarity across said isolation means for a test period during normal operation; and
a second means monitoring a voltage proportional to an input voltage to said isolation means and outputting an error signal if the monitored voltage remains at or rises above a first reference value during the test period.
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Accused Products
Abstract
An uninterruptible power supply wherein an isolation device is automatically tested during normal operation to ensure that it is capable of effectively isolating the input from an auxiliary power supply during emergency operation. The uninterruptible power supply includes an input for coupling to a main power supply, an output for connection to an electrical load, an auxiliary power supply and a selective isolation device configured to isolate the auxiliary power supply from the input during emergency operation. First components establish a reverse polarity across the isolation device for a test period during normal operation, and second components monitor a voltage proportional to the input voltage to the isolation device and output an error signal if the monitored voltage remains or rises above a first reference value during the test period.
42 Citations
11 Claims
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1. An uninterruptible power supply comprising:
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a supply input adapted to be connected to a main power supply;
an output adapted to be connected to an electrical load;
an auxiliary power supply;
a selective isolation means connected between said supply input and said auxiliary power supply for isolating said auxiliary power supply from said supply input during an emergency operation;
a first means establishing a reverse polarity across said isolation means for a test period during normal operation; and
a second means monitoring a voltage proportional to an input voltage to said isolation means and outputting an error signal if the monitored voltage remains at or rises above a first reference value during the test period. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method for testing a selective isolation means used in an uninterruptible power supply to isolate an auxiliary power supply from an input during emergency operation, comprising the steps of:
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establishing a reverse polarity across the isolation means for a test period during normal operation of the uninterruptible power supply;
monitoring a voltage proportional to an input voltage to the isolation means; and
outputting an error signal if the monitored voltage remains at or rises above a first reference value during the test period. - View Dependent Claims (11)
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Specification