Means of detecting faults in alternators

• US 20070013387A1
• Filed: 07/12/2005
• Published: 01/18/2007
• Est. Priority Date: 07/12/2005
• Status: Abandoned Application

• Current Assignee: Pratt & Whitney Canada Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Original Assignee: Pratt & Whitney Canada Corporation (Raytheon Technologies Corporation d/b/a RTX)
• Inventors: Smith, Michael, David Matthews, Peter
• Application Number:
  US11/178,294
• Publication Number:
  US 20070013387A1
• Time in Patent Office: Days
• US Class Current: 324/546
• CPC Class Codes: G01R 31/343 in operation

Abstract

A method and apparatus is disclosed for detecting one or more faults in a multi-phase alternator, wherein a phase sensing unit, comprising a star wound resistor assembly, senses each phase of the alternator and provides an indirect phase measure; further wherein a comparing unit, comprising an op amp, receives and compares each of the corresponding phase measures with a reference to provide a comparison result and wherein a fault detection unit receiving the comparison result and providing a fault condition signal in the case of a fault.

Claims

1. A method for detecting a fault in a multi-phase alternator, said method comprising:

providing a signal indicative of an indirect measure of at least two of said phases of said multi-phase alternator;

comparing said signal indicative of the indirect measure of the phases with a reference; and

detecting a fault condition using said comparison.

2. The method of claim 1, wherein said detecting a fault condition occurs when said comparison meets a given criteria.

3. The method of claim 2, further comprising providing said reference.

4. The method of claim 3, wherein said providing said reference comprises calculating a ratio between a positive DC supply of said multi-phase alternator and a 0 volt DC line to obtain said reference.

5. The method of claim 1, wherein said providing an indirect measure comprises taking said indirect measure at a connection point that is common to some of the phases.

7. The method of claim 1, wherein said providing an indirect measure comprises taking said indirect measure at a connection point that is common to all the phases.

8. The method of claim 7, wherein said providing an Indirect measure further comprises connecting a resistor between each of the phases and said connection point.

6. The method of claim 6, wherein said providing an indirect measure further comprises connecting a resistor between at least two of the phases and said connection point.

9. An apparatus for detecting a fault in a multi-phase alternator, said apparatus comprising:

a phase sensing unit for monitoring said multi-phase alternator and for reading a signal that indirectly measures at least two of said phases, thereby providing an indirect phase measure signal; and

a comparing unit for receiving and comparing said indirect phase measure signal with a given reference signal to provide a comparison result signal indicative of said comparison;

said comparison being used to detect said fault.

10. The apparatus of claim 9, further comprising a fault detection unit for receiving and using said comparison result signal for providing a fault condition signal indicative of a fault condition.

11. The apparatus of claim 10, wherein said phase sensing unit comprises a star wound resistor assembly comprising a plurality of resistors, each resistor being connected to a corresponding phase of said multi-phase alternator, said star wound resistor assembly comprising a star point to which each resistor is connected and from which is performed said sampling of said indirect phase measure signal.

12. The apparatus of claim 11, wherein said comparing unit comprises an operational amplifier receiving said indirect phase measure signal and a reference signal and providing said comparison result signal.

13. The apparatus of claim 12, wherein said comparing unit further comprises a monostable circuit receiving and using said comparison result signal to provide said fault condition signal.

14. The apparatus of claim 12, wherein said given reference comprises a ratio between a positive DC supply of said multi-phase alternator and a 0 volt DC line.

16. The apparatus of claim 14, wherein said comparing unit further comprises a monostable circuit receiving and using said comparison result signal to provide a fault condition signal.

15. An apparatus for detecting one or more faults in a multi-phase alternator, said apparatus comprising:

a phase sensing unit having a star wound resistor assembly comprising a plurality of resistors, each resistor being connected, at one end, to a corresponding phase of said multi-phase alternator and, at the other end, a common star point from which is read an indirect phase measure signal; and

a comparing unit having an operational amplifier receiving said indirect phase measure signal and a reference signal and providing therefrom a comparison result signal indicative of said comparison;

said comparison being used to detect said fault.