Three-Phase Detection Module

• US 20140247524A1
• Filed: 05/12/2014
• Published: 09/04/2014
• Est. Priority Date: 11/13/2007
• Status: Active Grant

• Current Assignee: Copeland Corporation LLC (Emerson Electric Company)
• Original Assignee: Emerson Climate Technologies Incorporated (Emerson Electric Company)
• Inventors: WU, Yunfeng, WANG, Yongbing
• Granted Patent: US 9,557,389 B2
• Time in Patent Office: Days
• US Class Current: 361/33
• CPC Class Codes: G01R 19/155 Indicating the presence of voltage
• CPC Class Codes: G01R 19/16566 Circuits and arrangements for comparing voltage or current with one or several thresholds and for indicating the result not covered by subgroups G01R19/16504, G01R19/16528, G01R19/16533
• CPC Class Codes: G01R 19/2513 Arrangements for monitoring electric power systems, e.g. power lines or loads; Logging
• CPC Class Codes: G01R 29/16 Measuring asymmetry of polyphase networks
• CPC Class Codes: G01R 31/42 AC power supplies
• CPC Class Codes: H02H 7/09 against over-voltage; against reduction of voltage; against phase interruption

Abstract

A method includes receiving N power signals, each having a different one of N phases, over N power supply lines, where N is an integer greater than two. The method further includes selectively activating a first switch to allow a first current to flow from a first one of the N power supply lines to a second one of the N power supply lines. The method includes generating a signal based on the first current, and selectively generating a phase failure signal when the signal is less than a predetermined threshold.

Claims

1. (canceled)

2. A monitoring apparatus connected, in parallel with a motor, to a plurality of power supply lines, each of the plurality of power supply lines having a different phase, the monitoring apparatus comprising:

a first isolator configured to selectively allow a first current to flow from a first power supply line of the plurality of power supply lines to a second power supply line of the plurality of power supply lines;

a second isolator configured to selectively allow a second current to flow from the second power supply line of the plurality of power supply lines to a third power supply line of the plurality of power supply lines; and

a control module configured to;

control the first isolator,

control the second isolator,

receive a first signal corresponding to a total current, wherein the total current includes both the first current and the second current, and

selectively generate a phase failure signal in response to the first signal indicating that a failure of at least one of the plurality of power supply lines has occurred.

3. The monitoring apparatus of claim 2 further comprising a third isolator configured to selectively allow a third current to flow from the third power supply line of the plurality of power supply lines to the first power supply line of the plurality of power supply lines, wherein the total current also includes the third current.

4. The monitoring apparatus of claim 3 wherein the control module is configured to:

sequentially activate the first isolator, the second isolator, and the third isolator; and

repeat the sequential activation.

5. The monitoring apparatus of claim 3 wherein the plurality of power supply lines consists of only the first power supply line, the second power supply line, and the third power supply line.

6. The monitoring apparatus of claim 5 wherein the monitoring apparatus is further connected to a neutral line associated with the plurality of power supply lines.

7. The monitoring apparatus of claim 3 wherein the first isolator comprises a first optocoupler, the second isolator comprises a second optocoupler, and the third isolator comprises a third optocoupler.

8. The monitoring apparatus of claim 2 wherein the first isolator comprises a first optocoupler and the second isolator comprises a second optocoupler.

9. The monitoring apparatus of claim 2 further comprising a third isolator configured to output the first signal to the control module in response to the total current.

10. The monitoring apparatus of claim 9 wherein the third isolator comprises an optocoupler.

11. The monitoring apparatus of claim 2 wherein the control module is configured to:

while the first isolator is activated, deactivate the second isolator; and

while the second isolator is activated, deactivate the first isolator.

12. The monitoring apparatus of claim 2 wherein the control module is configured to halt operation of the motor in response to generation of the phase failure signal.

13. The monitoring apparatus of claim 2 wherein:

the control module is configured to activate the first isolator for a predetermined duration;

the plurality of power supply lines carry periodic power signals characterized by a first period; and

the predetermined duration is based on a length of the first period.

14. The monitoring apparatus of claim 13 wherein the predetermined duration is equal to the length of the first period plus a predetermined offset.

15. The monitoring apparatus of claim 2 wherein the first signal is directly proportional to the total current.

16. The monitoring apparatus of claim 2 further comprising generating the phase failure signal in response to a peak value of the first signal over a predetermined period of time being less than a predetermined threshold.

17. A motor system comprising:

the monitoring apparatus of claim 2; and

the motor.

18. A compressor system comprising:

the motor system of claim 17; and

a compressor driven by the motor.

19. A method of operating a monitoring apparatus connected, in parallel with a motor, to a plurality of power supply lines, each of the plurality of power supply lines having a different phase, the method comprising:

selectively activating a first isolator to allow a first current to flow from a first power supply line of the plurality of power supply lines to a second power supply line of the plurality of power supply lines;

selectively activating a second isolator to allow a second current to flow from the second power supply line of the plurality of power supply lines to a third power supply line of the plurality of power supply lines;

receiving a first signal corresponding to a total current, wherein the total current includes both the first current and the second current; and

selectively generating a phase failure signal in response to the first signal indicating that a failure of at least one of the plurality of power supply lines has occurred.

20. The method of claim 19 further comprising selectively activating a third isolator to allow a third current to flow from the third power supply line of the plurality of power supply lines to the first power supply line of the plurality of power supply lines, wherein the total current also includes the third current.

21. The method of claim 20 further comprising:

sequentially activating the first isolator, the second isolator, and the third isolator; and

repeating the sequential activation.

22. The method of claim 20 wherein the plurality of power supply lines consists of only the first power supply line, the second power supply line, and the third power supply line.

23. The method of claim 22 wherein the monitoring apparatus is further connected to a neutral line associated with the plurality of power supply lines.

24. The method of claim 19 further comprising:

while the first isolator is activated, deactivating the second isolator; and

while the second isolator is activated, deactivating the first isolator.

25. The method of claim 19 further comprising halting operation of the motor in response to generation of the phase failure signal.

26. The method of claim 19 further comprising activating the first isolator for a predetermined duration, wherein the plurality of power supply lines carry periodic power signals characterized by a first period, and wherein the predetermined duration is based on a length of the first period.

27. The method of claim 26 wherein the predetermined duration is equal to the length of the first period plus a predetermined offset.

28. The method of claim 19 wherein the first signal is directly proportional to the total current.

29. The method of claim 19 further comprising generating the phase failure signal in response to a peak value of the first signal over a predetermined period of time being less than a predetermined threshold.