| US 7,518,838 B1 | ||
| Protection of variable frequency power systems from excessive peak electrical potentials | ||
| Wayne H. Oldenburg, Roscoe, Ill. (US); and Nicholas Allen Lemberg, Milwaukee, Wis. (US) | ||
| Assigned to Hamilton Sundstrand Corporation, Windsor Locks, Conn. (US) | ||
| Filed on Nov. 15, 2007, as Appl. No. 11/940,342. | ||
| Int. Cl. H02H 7/09 (2006.01) | ||
| U.S. Cl. 361—33 [361/1; 361/21; 361/23; 361/55; 361/56; 361/93.1; 361/95; 363/50] | 27 Claims |
| 1. A method of protecting an electromechanical power transfer system from excessive peak electrical potentials, the power
transfer system comprising a prime mover, a dynamoelectric machine coupled to the prime mover for generating multiphase alternating
current (AC) power, and at least one multiphase AC electrical load coupled to the dynamoelectric machine by way of a multiphase
AC power bus, the dynamoelectric machine having a control coil responsive to control current for varying power supplied to
the electrical load, comprising the steps of:
analysing electrical potentials on the power bus to generate analysed power bus characteristics;
comparing the analysed power bus characteristics to predetermined power bus characteristics;
simultaneously shunting power across the power bus and reducing control current to the control coil for the dynamoelectric
machine when the analysed power bus characteristics approximate the predetermined power bus characteristics to reduce the
measured electrical potentials; and
simultaneously terminating the shunt of power across the power bus and restoring the level of control current to the control
coil for the dynamoelectric machine after a selected delay period to automatically restore power to the electrical load.
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