Motor protection circuit
First Claim
1. Apparatus for protecting an electrical motor connectable to an electric power source through a switchable circuit breaker means comprising:
- a first protection circuit having first protection means for sensing a first plurality of elecrical parameters at the power source detrimental to the motor and first operation means for causing the circuit breaker to switch to an open condition disconnecting the motor from the power source,said first operation means being actuatable upon the sensing by the first detection circuit of a malfunction of any one of said first plurality of electrical parameters, anda second protection circuit comprising second detection means for sensing a second plurality of parameters on the side of the circuit breaker connected to the motor detrimental to the motor,second operation means for causing the circuit breaker to switch to an open condition and disconnect the motor from the power source,said second operation means being actuatable upon the sensing by said second detection circuit of any one of said detrimental second plurality of electrical parameters.
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Accused Products
Abstract
A protection circuit for multi-phase motors provides circuits for protecting a motor against low voltage, phase reversal or loss of a phase and other improper operating conditions on both the line side and the motor side of the main motor contactors. The line and motor side circuits are interrelated such that an unsafe condition on either side of the contactors causes the contactors to be opened. A time delay circuit on the motor side of the contactors prevents interruption of the holding circuit until conditions on the motor side of the contacts have been established and sensed for operation, proper or otherwise, during motor start up.
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Citations
16 Claims
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1. Apparatus for protecting an electrical motor connectable to an electric power source through a switchable circuit breaker means comprising:
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a first protection circuit having first protection means for sensing a first plurality of elecrical parameters at the power source detrimental to the motor and first operation means for causing the circuit breaker to switch to an open condition disconnecting the motor from the power source, said first operation means being actuatable upon the sensing by the first detection circuit of a malfunction of any one of said first plurality of electrical parameters, and a second protection circuit comprising second detection means for sensing a second plurality of parameters on the side of the circuit breaker connected to the motor detrimental to the motor, second operation means for causing the circuit breaker to switch to an open condition and disconnect the motor from the power source, said second operation means being actuatable upon the sensing by said second detection circuit of any one of said detrimental second plurality of electrical parameters. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method for protecting an electrical motor connected to the electrical power source through a switchable circuit breaker means for disconnecting the electric motor from the power source comprising the steps of providing of a first and second protection means, and connecting the first protection means to sense electrical parameters between the power source and the circuit breaker means detrimental to the motor and the second protection means to sense electrical parameters between the circuit breaker means and the electrical motor detrimental to the motor.
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9. An apparatus for protecting an electrical motor operatively connectable to an electrical power line having more than two leads through a switchable circuit breaker means comprising:
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a first protection circuit having a first detection means for sensing electrical parameters in the connection between the circuit breaker means and the motor, and operations means for causing the circuit breaker to open the connection between the electrical power source and the motor, said operation means being actuatable upon the sensing by said first detection means of electrical parameters detrimental to the motor, said detection means being powered from more than two leads of the power source and comprising means for sensing and opening said breaker means upon substantial reduction of voltage on one of said power supply leads. - View Dependent Claims (10)
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11. A protection circuit for a multi-phase motor adapted to be connected to electrical leads having multiple phases thereacross comprising
first means for sensing an abnormal electrical parameter on said electrical leads, a plurality of leads, a multi-phase circuit breaker for selectively connecting said plurality of leads to said electrical leads, second means for sensing low voltage concurrently on all of said first and/or second plurality of leads, first control means for selectively initiating actuation of said circuit breaker to interconnect said leads and said electrical leads, said first control means including means for preventing actuation of said circuit breaker upon said first means detecting said abnormal electrical parameter on said electrical leads, and second control means for deactivating said circuit breaker upon detection of low voltage on all phases of said leads.
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12. A protection circuit for a multi-phase motor adapted to be connected to electrical leads having multiple phases thereacross comprising
first means for sensing an abnormal electrical parameter on said electrical leads, a plurality of leads, a multi-phase circuit breaker for selectively connecting said plurality of leads to said electrical leads, second means for sensing reversal of phase of the voltage on one of said plurality of leads, first control means for selectively initiating actuation of said circuit breaker to interconnect said leads and said second leads, said first control means including means for preventing actuation of said circuit breaker upon said first means detecting said abnormal electrical parameter on said electrical leads, and second control means for deactivating said circuit breaker upon detection of a reversal of phase on one of said plurality of leads.
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13. A protection circuit for a multi-phase motor comprising
first means for sensing low voltage on all phases of first voltage supply leads, second means for sensing low voltage on all phases of second voltage supply leads, a multi-phase circuit breaker, said second voltage supply leads being connected to a multi-phase motor and selectively through said circuit breaker to the first voltage supply leads, control means for selectively initiating actuation of said circuit breaker to connect said second voltage supply leads to said first voltage supply leads, said control means including means for preventing actuation of said circuit breaker upon said first means sensing low voltage on all phases of said first voltage supply leads, and means for deactivating said circuit breaker upon detection of low voltage on all phases of said first and/or second voltage supply leads.
Specification