Drive protection monitor for motor and amplifier
First Claim
1. An apparatus for monitoring the temperature of an inaccessible portion of an electrical current carrying device that cannot be directly measured easily comprising:
- means for establishing a reference temperature value comprising means for continuously measuring an accessible temperature in the vicinity of the current carrying device;
means for measuring the power dissipated in the current carrying device;
a digital computer;
means for inputting to the digital computer, the reference temperature value, the power dissipated in the current carrying device, the thermal resistances and thermal time constants of the thermal model simulating the current carrying device to the reference temperature; and
means comprising the digital computer for continuously calculating a differential temperature based upon the power dissipation and thermal model and adding the reference temperature thereto.
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Accused Products
Abstract
An apparatus for monitoring the temperature of an inaccessible portion of an electrical current carrying device that cannot be directly measured easily comprises circuits for establishing a reference temperature value in the vicinity of the current carrying device and measuring the power dissipated in the current carrying device, a digital computer having ports for inputting the reference temperature value, the power dissipated in the current carrying device, the thermal resistances and thermal time constants of the thermal model simulating the current carrying device to the reference temperature, and a program stored in the digital computer for continuously calculating a differential temperature based upon the power dissipation and thermal model and adding the reference temperature thereto.
77 Citations
19 Claims
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1. An apparatus for monitoring the temperature of an inaccessible portion of an electrical current carrying device that cannot be directly measured easily comprising:
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means for establishing a reference temperature value comprising means for continuously measuring an accessible temperature in the vicinity of the current carrying device; means for measuring the power dissipated in the current carrying device; a digital computer; means for inputting to the digital computer, the reference temperature value, the power dissipated in the current carrying device, the thermal resistances and thermal time constants of the thermal model simulating the current carrying device to the reference temperature; and means comprising the digital computer for continuously calculating a differential temperature based upon the power dissipation and thermal model and adding the reference temperature thereto. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 14, 18)
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12. A bridge amplifier having four output semiconductors in two pairs, each pair connected in series between the bus voltage and ground, the output of the semiconductor bridges being across the junctions between the semiconductors in both pairs, a driver for controlling the semiconductors in one pair to connect the output common thereto to either the bus voltage or to ground, a rapid response driver with bus voltage input for controlling the semiconductors in the other pair such that the voltage on the junction of one pair is the bus voltage minus the voltage of the junction on the other pair, whereby the voltage across the conducting semiconductor of one pair is essentially the same as the voltage across the conducting semiconductor of the other pair.
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15. An apparatus for monitoring the temperature of an inaccessible portion of an electrical current carrying device that cannot be directly measured easily comprising:
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means for establishing a reference temperature value in the vicinity of the current carrying device; means for measuring the power dissipated in the current carrying device by measuring the current through the device and calculating the dissipation based upon the resistance of the device where said resistance is adjusted for the temperature of the device or the current through the device; a digital computer; means for inputting to the digital computer, the reference temperature value, the power dissipated in the current carrying device, the thermal resistances and thermal time constants of the thermal model simulating the current carrying device to the reference temperature; and means comprising the digital computer for continuously calculating a differential temperature based upon the power dissipation and thermal model and adding the reference temperature thereto. - View Dependent Claims (16, 17)
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19. An apparatus for monitoring the temperature of an inaccessible portion of an electrical current carrying device that cannot be directly measured easily comprising:
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means for establishing a reference temperature value in the vicinity of the current carrying device; means for measuring the power dissipated in the current carrying device; a digital computer; means for inputting to the digital computer, the reference temperature value, the power dissipated in the current carrying device, the thermal resistances and thermal time constants of the thermal model simulating the current carrying device to the reference temperature; and means comprising the digital computer for continuously calculating a differential temperature based upon the power dissipation and thermal model and adding the reference temperature thereto wherein the differential temperature comprises two components, a positive differential resulting from power dissipation, if any, and a negative differential based upon heat transfer away from the device.
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Specification