Protection arrangement for a brushless synchronous machine
First Claim
1. In a protection arrangement for protecting a brushless synchronous machine against overvoltages at a field winding which is connected to a rotating excitation rectifier fed from an exciter machine which includes a solid state switching element for short circuiting the field winding if overvoltages occur, the improvement comprising:
- a. means for forming a first input voltage proportional, by a first proportionality constant, to the primary voltage of the exciter machine;
b. means for forming a second input voltage proportional, by a second proportionality constant, to the primary current of the exciter machine, the two proportionality constants being chosen so that the absolute value of the second input voltage in normal operation of the synchronous machine is lower and, if the field winding is short circuited, is higher than the first input voltage; and
c. voltage comparison means having said first and second voltages as input and providing at its output an indicating signal.
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Accused Products
Abstract
In a protective arrangement for protecting a brushless synchronous machine against overvoltage at a field winding which is connected to a rotating excitation rectifier which is fed from an exciter machine, in which the field winding is short circuited by means of a solid state switching element when overvoltages occur, a voltage comparison means is provided to which are fed as respective first and second inputs, a first input voltage proportional to the primary voltage of the exciter machine and a second input voltage proportional to the primary current of the exciter machine with the proportionality constant chosen such that for normal operation of the synchronous machine the absolute value of the second input voltage is lower than the first input voltage and for operation when the field winding is short circuited, the absolute value of the second input voltage is greater than the first input voltage.
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Citations
12 Claims
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1. In a protection arrangement for protecting a brushless synchronous machine against overvoltages at a field winding which is connected to a rotating excitation rectifier fed from an exciter machine which includes a solid state switching element for short circuiting the field winding if overvoltages occur, the improvement comprising:
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a. means for forming a first input voltage proportional, by a first proportionality constant, to the primary voltage of the exciter machine; b. means for forming a second input voltage proportional, by a second proportionality constant, to the primary current of the exciter machine, the two proportionality constants being chosen so that the absolute value of the second input voltage in normal operation of the synchronous machine is lower and, if the field winding is short circuited, is higher than the first input voltage; and c. voltage comparison means having said first and second voltages as input and providing at its output an indicating signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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Specification