Electricity: motive power systems – Induction motor systems – With voltage source connected to motor secondary
Patent
1989-08-23
1991-06-11
Ip, Paul
Electricity: motive power systems
Induction motor systems
With voltage source connected to motor secondary
318798, 322 32, 322 25, 290 4R, H02P 930
Patent
active
050235370
ABSTRACT:
The problem of detecting low frequency faults is solved in a VSCF control system which is operated in a start mode to start an engine (18) using a brushless synchronous generator operating as a motor (12). The motor (12) receives power through a feeder (52) from a converter (36) which is coupled through an additional feeder (44) to a source (42) of AC power. During normal, non-fault conditions, the sum of the input currents to the converter (36) and the sum of the output currents from the converter (36) must each be zero. When a fault condition exists, then one or both of these currents will be non-zero, depending upon the location of the fault. A single current sensor (56) is used to sense feeder faults by positioning the sensor to read the current through the converter input feeder (44). As long as no feeder to ground fault condition exists, then the current sensor (44) senses zero current. If a non-zero current is sensed, then it is assumed that a fault condition exists.
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Ip Paul
Sundstrand Corporation
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