Multifunction dynamoelectric protection system
First Claim
1. A protection system for a dynamoelectric machine comprisinga source of power and switching means for switching the power to and from the dynamoelectric machine,a first control means, the first control means being a temperature protection control means having at least one input and an output and two operating states, temperature responsive sensor means coupled to one input of the first control means,a second control means, the second control means being a shorted sensor control means having at least one input and an output and two operating states, the output of the second control means coupled to the switching means, the output of the first control means coupled to the one input of the second control means,a third control means, the third control means being a time delay control means having at least one input and an output and two operating states, the output of the third control means coupled to the one input of the first control means, a timing network coupled to the one input of the third control means,a fourth control means, the fourth control means being a low voltage control means having at least one input and an output and two operating states, line voltage sensing means coupled to the one input of the fourth control means,a fifth control means, the fifth control means being a pressure control means having at least one input and an output and two operating states, the output of the fifth control means coupled to the one input of the first control means, a pressure switch network coupled to the one input of the fifth control means,sixth control means having at least one input and an output and two operating states, the output of the fifth control means coupled to the one input of the sixth control means, the output of the sixth control means coupled to the one input of the second control means,seventh control means having at least one input and an output and two operating states, the output of the seventh control means coupled to the one input of the sixth control means, dynamoelectric machine current sensing means having an output signal indicative of the existence of such current, the signal fed into the one input of the seventh control means, and eighth control means having at least one input and an output and two operating states, the output of the seventh control means coupled to the one input of the eighth control means and the output of the eighth control means coupled to the one input of the second control means.
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Accused Products
Abstract
A protection system for a dynamoelectric machine providing a plurality of protective functions comprises a module having as a first function over temperature protection including thermal sensors adapted to be placed in heat transfer relation with the windings of the machine. The sensors which may be connected in series or in parallel are connected to a sensing circuit provided with shorted sensor protection. When connected in parallel a channel is provided for each sensor and is isolated from one another. Other functions include a minimum off delay timer which prevents rapid cycling of the machine. An oil pressure timer particularly useful with a compressor motor to sense oil pressure between the output of the oil pump and the crankcase in order to deenergize the motor should there be inadequate oil pressure for a selected period of time, a low voltage cut out network in the event of the occurrence of low voltage conditions, and a circuit to facilitate use of controls in the output side of the system if desired while permitting operation of the system only on the condition of output current flow.
The minimum off delay timer can be modified to provide a manual reset circuit which will lock out or prevent energization of the machine each time the protection circuit is tripped. Reset can be accomplished only by removing power to the module and reapplying said power.
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Citations
28 Claims
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1. A protection system for a dynamoelectric machine comprising
a source of power and switching means for switching the power to and from the dynamoelectric machine, a first control means, the first control means being a temperature protection control means having at least one input and an output and two operating states, temperature responsive sensor means coupled to one input of the first control means, a second control means, the second control means being a shorted sensor control means having at least one input and an output and two operating states, the output of the second control means coupled to the switching means, the output of the first control means coupled to the one input of the second control means, a third control means, the third control means being a time delay control means having at least one input and an output and two operating states, the output of the third control means coupled to the one input of the first control means, a timing network coupled to the one input of the third control means, a fourth control means, the fourth control means being a low voltage control means having at least one input and an output and two operating states, line voltage sensing means coupled to the one input of the fourth control means, a fifth control means, the fifth control means being a pressure control means having at least one input and an output and two operating states, the output of the fifth control means coupled to the one input of the first control means, a pressure switch network coupled to the one input of the fifth control means, sixth control means having at least one input and an output and two operating states, the output of the fifth control means coupled to the one input of the sixth control means, the output of the sixth control means coupled to the one input of the second control means, seventh control means having at least one input and an output and two operating states, the output of the seventh control means coupled to the one input of the sixth control means, dynamoelectric machine current sensing means having an output signal indicative of the existence of such current, the signal fed into the one input of the seventh control means, and eighth control means having at least one input and an output and two operating states, the output of the seventh control means coupled to the one input of the eighth control means and the output of the eighth control means coupled to the one input of the second control means.
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13. A protection system for a deynamoelectric machine comprising
a source of power and switching means for switching the power to and from the dynamoelectric machine, control means adapted to control the switching mmeans comprising first and second voltage comparators each having two inputs and an output, a source of d.c. power, a first voltage divider connected between the d.c. power source and common comprising a reference resistor and a temperature dependent resistor forming a first junction therebetween, the first junction connected to one input of the first comparator, a second voltage divider ccomprising two resistors forming a second junction therebetween, the second voltage divider serially connected to another resistance, the voltage divider and the said another resistor connected between the d.c. power source and common, the second junction connected to one input of the second comparator, reference voltage means connected to the other inputs of the first and second comparators, a diode coupled between the first and second junctions, the output of first comparator connected to a point between the second voltage divider and the said another resistance, so that upon a selected change in temperature and concomitant change in resistance of the temperature dependent resistor or upon shorting of the temperature dependent resistor, the output of the second comparator will switch and cause the switching means to interrupt power to the machine.
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14. A protection system for a dynamoelectric machine comprising
switching means for switching a source of power to and from the machine, a bridge circuit means controlling operation of the switching means, the bridge circuit means including a resistor bridge, the resistor bridge including a temperature dependent resistor responsive to a predetermined temperature condition, trigger means responsive to an unbalance of the bridge to operate the switching means, a time delay means having a time delay voltage comparator with two inputs and one output, a time delay voltage divider comprising two resistors forming a time delay junction therebetween, a diode, the inputs of the time delay voltage comparator connected to the time delay junction with the diode interposed therebetween, a capacitor connected across one of the two resistors of the time delay voltage dividers and the output of the time delay comparator coupled to the trigger means.
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15. A protection system for a dynamoelectric machine comprising
switching means for switching a source of power to and from the machine, a bridge circuit means controlling operation of the switching means, the bridge circuit means including a resistor bridge, the resistor bridge including a temperature dependent resistor responsive to a predetermined temperature condition, trigger means responsive to an unbalance of the bridge to operate the switching means, manual reset means having a manual reset voltage comparator with two inputs and an output, a diode connected between the two inputs of the manual reset voltage comparator, one input of the manual reset comparator connected through a resistor to a power source and to another resistor to the trigger means, the second input of the manual reset comparator connected to common through a capacitor and to the output of the manual reset comparator through a resistance, the ouput of the manual reset comparator coupled to the trigger means.
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19. A protection system for a dynamoelectric machine comprising
switching means for switching a source of power to and from the machine, a bridge circuit means controlling operation of the switching means, the bridge circuit means including a resistor bridge, the resistor bridge including a junction formed between a temperature dependent resistor responsive to a predetermined temperature condition and a reference resistor, trigger means responsive to an unbalance of the bridge to operate the switching means, output sensing control means comprising first and second output sensing voltage comparators each having two inputs and an output, a coil connected between two resistors which are in turn connected between a power source aand common, the two inputs of the first output sensing comparator connected to opposite ends of the coil, a power line carrying power to the machine disposed about the coil to form at least a single turn thereabout, the output of the first output sensing comparator connected through a capacitor to an input of the second output sensing comparator, the output of the second output sensing comparator coupled to the trigger means.
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21. A protection system for a dynamoelectric machine which has a power supply, a solid state power switch adapted to energize the machine, the power switch having a control element, contacts adapted to move into and out of engagement connected to the control element, electromagnetic coil means coupled to the contacts to control their position, and a control current switch to control the engergization of the electromagnetic coil means comprising
a temperature control network including a voltage comparator having two inputs and an output, at least one temperature dependent resistor adapted to provide a signal to one of the inputs of the temperature control comparator indicative of the temperature of the temperature dependent resistor, a shorted sensor control network including a shorted sensor voltage comparator having two inputs and an output, the output of the shorted sensor control comparator determining the state of energization of the control current switch, the output of the temperature control comparator coupled to one of the inputs of the shorted sensor comparator and adapted to control its output state so that subjection of the sensor to a preselected temperature will cause the temperature control comparator to switch from one state to another which will in turn cause the shorted sensor comparator to switch from one state to another deenergizing the control current switch and deenergizing the electromagnetic coil means so that the contacts move out of engagement to deenergize the power switch and the machine.
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27. A system for a dynamoelectric machine comprising switching means for switching a source of power to and from the machine,
a bridge circuit means controlling operation of the switching means, trigger means responsive to an unbalance of the bridge to operate the switching means, a time delay means having a time delay voltage comparator with two inputs and one output, a time delay voltage divider comprising two resistors forming a time delay junction therebetween, a diode, the inputs of the time delay voltage comparator connected to the time delay junction with the diode interposed therebetween, a capacitor connected across one of the two resistors of the time delay voltage dividers and the output of the time delay comparator coupled to the trigger means.
Specification