Phase sequence correcting system for three-phase AC power
First Claim
1. A phase sequence correcting system for coupling a three-terminal, three-phase AC power supply to a three-terminal, phase-sensitive load to apply three-phase power to the load in a desired rotation sequence, comprising:
- phase sequence sensing means for detecting the phase rotation sequence of the three-phase AC power supply;
a memory device;
write-in means, responsive to said sensing means, for actuating said memory device to store information therein representing the phase sequence of the AC power supply;
inhibiting means for inhibiting the operation of said write-in means, when a predetermined time delay interval has elapsed after the system has been rendered operable, in order to lock the stored phase sequence information in said memory device;
read-out means for reading out the stored phase sequence information from said memory device;
and switching means, responsive to said read-out means, for interconnecting the three terminals of the three-phase AC power supply to the three terminals of the load in accordance with the interconnection pattern required to provide the load with the desired phase sequence.
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Accused Products
Abstract
The phase sequence of a three-phase AC power supply is detected and information representing that sequence is stored in a memory device, such as a flip-flop. Since the power supply, once it is energized, may require a few seconds to stabilize (such as may be the case when the power source is a diesel generator), the information fed to the memory device is likely to change during the stabilizing period. At the end of that period, however, the stored information represents the true phase sequence of the AC power supply, and at that time the information is read out and used to actuate switching apparatus to interconnect the three-phase AC power supply to the three terminals of a phase-sensitive load (such as a three-phase AC motor) in the manner necessary to provide the load with a desired phase rotation sequence. After the stabilizing period, the input circuitry of the memory device is inhibited so that the stored information representing the true phase sequence will be locked into the memory device and so that the device will be insensitive to any fluctuating voltages, frequency or noise that could otherwise cause an accidental phase reversal while the load is energized.
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Citations
5 Claims
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1. A phase sequence correcting system for coupling a three-terminal, three-phase AC power supply to a three-terminal, phase-sensitive load to apply three-phase power to the load in a desired rotation sequence, comprising:
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phase sequence sensing means for detecting the phase rotation sequence of the three-phase AC power supply; a memory device; write-in means, responsive to said sensing means, for actuating said memory device to store information therein representing the phase sequence of the AC power supply; inhibiting means for inhibiting the operation of said write-in means, when a predetermined time delay interval has elapsed after the system has been rendered operable, in order to lock the stored phase sequence information in said memory device; read-out means for reading out the stored phase sequence information from said memory device; and switching means, responsive to said read-out means, for interconnecting the three terminals of the three-phase AC power supply to the three terminals of the load in accordance with the interconnection pattern required to provide the load with the desired phase sequence. - View Dependent Claims (2, 3, 4, 5)
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Specification