Determining asynchronous motor couple
First Claim
1. A device for the determination of the couple provided by an asynchronous motor, said device comprising:
- (i) means for determining the mean power absorbed from a polyphase current supply, said means including means for measuring the current in a phase, means for generating a single phase voltage from a combination of the voltages between the respective phases, means for deriving the product of the said current and single phase voltage, means for determining the mean value of the said product; and
(ii) means for subtracting from said product, before said determination of the mean value thereof, a quantity which is a function of the said current, and which substantially represents the losses in the motor.
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Accused Products
Abstract
A device determines the mean power absorbed from a current supply by measuring the current in a phase, and the voltage between two phases, determining the product thereof, and integrating the product.
A first potentiometer provides a proportion of the voltage which is an image of the current, and subtracts it from that voltage between phases. A second potentiometer provides a proportion of the voltage between phases and subtracts if from the product. A third potentiometer provides a proportion of a constant voltage and subtracts it from that product. The third potentiometer is adjusted so that the output power of the integrator shall be zero when the motor rotates under no-load condition.
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Citations
12 Claims
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1. A device for the determination of the couple provided by an asynchronous motor, said device comprising:
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(i) means for determining the mean power absorbed from a polyphase current supply, said means including means for measuring the current in a phase, means for generating a single phase voltage from a combination of the voltages between the respective phases, means for deriving the product of the said current and single phase voltage, means for determining the mean value of the said product; and (ii) means for subtracting from said product, before said determination of the mean value thereof, a quantity which is a function of the said current, and which substantially represents the losses in the motor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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Specification