US5058031A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Multilevel phase unbalance compressor motor protection system
Assignee: Trane International Inc
•
Filing: 1990-03-30
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Granted: 1991-10-15
•
Expires: 2010-03-30
Abstract
Abstract A method of protecting the compressor motor of a refrigeration system using a multiphase AC power source. The method comprises the steps of monitoring each phase of the power supply to the compressor motor; calculating the average phase for the phases of the AC power supply; determining a maximum phase unbalance deviation from the average phase; determining if a first level of phase unbalance protection is active; setting a system protection level as the first level of phase unbalance protection if the first level is active; setting the system protection level as a second higher level of phase unbalance protection if the first level is not active; and initiating a compressor motor shutdown if the system protection level is exceeded by the maximum unbalanced phase deviation.
Inventors
- 👤 Robert M. Swanson
- 👤 Paul C. Rentmeester
- 👤 David M. Foye
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 03:54
CPC Classifications
H; H02; H02H; H02H7/00; H02H7/08; H02H7/09
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
130 words
A method of protecting a compressor motor of a refrigeration system using a multiphase AC power supply comprising the steps of: monitoring each current or voltage phase of the power supply to the compressor motor; calculating an average phase for the current or voltage phases of the AC power supply; determining a maximum phase unbalance deviation from the average phase; determining if a first level of phase unbalance protection is active; setting a system protection level as the first level of phase unbalance protection if the first level is active; setting the system protection level as a second higher level of phase unbalance protection if the first level is not active; and initiating a compressor motor shutdown if the system protection level is exceeded by the maximum unbalance phase deviation.
Claim 2
Independent Claim
130 words
A method of protecting a compressor motor of a refrigeration system using a multiphase AC power supply comprising the steps of: monitoring each current or voltage phase of the power supply to the compressor motor; calculating an average phase for the current or voltage phases of the AC power supply; determining a maximum phase unbalance deviation from the average phase; determining if a first level of phase unbalance protection is active; setting a system protection level as the first level of phase unbalance protection if the first level is active; setting the system protection level as a second higher level of phase unbalance protection if the first level is not active; and initiating a compressor motor shutdown if the system protection level is exceeded by the maximum unbalance phase deviation.
Claim 3
Dependent Claim
30 words
The method of claim 1 including the step of setting the first level of phase unbalance protection to be a first value which prevents potential damage to the compressor motor.
Claim 4
Dependent Claim
36 words
The system of claim 2 including the step of setting the second level of phase unbalance protection to be a second value which prevents potential damage to critical components in a compressor motor safety protection system.
Claim 5
Dependent Claim
24 words
The system of claim 3 including the step of setting the first value to represent a deviation of approximately 15% from the average phase.
Claim 6
Dependent Claim
24 words
The method of claim 4 including the step of setting the second value to represent a deviation of approximately 30% from the average phase.
Claim 7
Dependent Claim
29 words
The method of claim 5 wherein the step of calculating average phase includes the step of determining a third value for each phase of current at a given time.
Claim 8
Dependent Claim
27 words
The method of claim 1 wherein the step of calculating average phase includes the step of determining a value for each of current at a given time.
Claim 9
Dependent Claim
50 words
The method of claim 7 wherein the step of determining maximum phase unbalance deviation further includes the steps of comparing the value for each phase of current to the average phase, and selecting as the maximum phase unbalance deviation whichever of the values differs the most from the average phase.
Claim 10
Dependent Claim
21 words
The method of claim 1 including the further step of delaying the compressor motor shutdown for a predetermined amount of time.
Claim 11
Dependent Claim
18 words
The method of claim 9 wherein the time delay is in the range of 5 to 30 seconds.
Claim 12
Dependent Claim
12 words
The method of claim 9 wherein the time delay is 15 seconds.
Claim 13
Dependent Claim
41 words
The method of claim 1 wherein the compressor motor has a rated load amperage and including the further step of bypassing the first level of protection if the average phase is less than 80% of the compressor motor's rated load amperage.
Claim 14
Dependent Claim
27 words
The method of claim 1 wherein the step of calculating average phase includes the step of determining a voltage value for each phase at a given time.
Claim 15
Dependent Claim
148 words
Apparatus for protecting a compressor motor of a refrigeration system using a multiphase AC power source comprising: a compressor motor; a multiphase AC power supply; means for monitoring each current or voltage phase of the power supply to the compressor motor; means for calculating an average phase for the current or voltage phases of the AC power supply; means for determining a maximum phase unbalance deviation from the average phase; means for determining if a first level of phase unbalance protection is active; means for setting a system protection level as the first level of phase unbalance protection if the first level is active; means for setting the system protection level as a second higher level of phase unbalance protection if the first level is not active; and means for initiating a compressor motor shutdown if the system protection level is exceeded by the maximum unbalance phase deviation.
Claim 16
Dependent Claim
148 words
Apparatus for protecting a compressor motor of a refrigeration system using a multiphase AC power source comprising: a compressor motor; a multiphase AC power supply; means for monitoring each current or voltage phase of the power supply to the compressor motor; means for calculating an average phase for the current or voltage phases of the AC power supply; means for determining a maximum phase unbalance deviation from the average phase; means for determining if a first level of phase unbalance protection is active; means for setting a system protection level as the first level of phase unbalance protection if the first level is active; means for setting the system protection level as a second higher level of phase unbalance protection if the first level is not active; and means for initiating a compressor motor shutdown if the system protection level is exceeded by the maximum unbalance phase deviation.
Claim 17
Independent Claim
123 words
A method of protecting a compressor motor of a refrigeration system using a multiphase AC power supply comprising the steps of: monitoring each phase current of the power supply to the compressor motor; calculating an average phase current for the phases of the AC power supply; determining a maximum deviation from the average phase current; determining if a first level of phase unbalance protection is active; setting a system protection level as the first level of phase unbalance protection if the first level is active; setting the system protection level as a second higher level of phase unbalance protection if the first level is not active; and initiating a compressor motor shutdown if the system protection level is exceeded by the maximum deviation.
Claim 18
Independent Claim
123 words
A method of protecting a compressor motor of a refrigeration system using a multiphase AC power supply comprising the steps of: monitoring each phase current of the power supply to the compressor motor; calculating an average phase current for the phases of the AC power supply; determining a maximum deviation from the average phase current; determining if a first level of phase unbalance protection is active; setting a system protection level as the first level of phase unbalance protection if the first level is active; setting the system protection level as a second higher level of phase unbalance protection if the first level is not active; and initiating a compressor motor shutdown if the system protection level is exceeded by the maximum deviation.
Claim 19
Dependent Claim
144 words
Apparatus for protecting a motor of a refrigeration system using a multiphase AC power supply comprising: a motor; a multiphase AC power supply; means for monitoring each current or voltage phase of the power supply to the motor; means for calculating an average phase for the current or voltage phases of the AC power supply; means for determining a maximum phase unbalance deviation from the average phase; means for determining if a first level of phase unbalance protection is active; means for setting a system protection level as the first level of phase unbalance protection if the first level is active; means for setting the system protection level as a second higher level of phase unbalance protection if the first level is not active; and means for initiating a motor shutdown if the system protection level is exceeded by the maximum unbalance phase deviation.
Claim 20
Dependent Claim
144 words
Apparatus for protecting a motor of a refrigeration system using a multiphase AC power supply comprising: a motor; a multiphase AC power supply; means for monitoring each current or voltage phase of the power supply to the motor; means for calculating an average phase for the current or voltage phases of the AC power supply; means for determining a maximum phase unbalance deviation from the average phase; means for determining if a first level of phase unbalance protection is active; means for setting a system protection level as the first level of phase unbalance protection if the first level is active; means for setting the system protection level as a second higher level of phase unbalance protection if the first level is not active; and means for initiating a motor shutdown if the system protection level is exceeded by the maximum unbalance phase deviation.
Claim 21
Independent Claim
127 words
A method of protecting a motor of a refrigeration system using a multiphase AC power supply comprising the steps of: monitoring each current or voltage phase of the power supply to the motor; calculating an average phase for the current or voltage phases of the AC power supply; determining a maximum phase unbalance deviation from the average phase; determining if a first level of phase unbalance protection is active; setting a system protection level as the first level of phase unbalance protection if the first level is active; setting the system protection level as a second higher level of phase unbalance protection if the first level is not active; and initiating a motor shutdown if the system protection level is exceeded by the maximum unbalance phase deviation.
Claim 22
Independent Claim
127 words
A method of protecting a motor of a refrigeration system using a multiphase AC power supply comprising the steps of: monitoring each current or voltage phase of the power supply to the motor; calculating an average phase for the current or voltage phases of the AC power supply; determining a maximum phase unbalance deviation from the average phase; determining if a first level of phase unbalance protection is active; setting a system protection level as the first level of phase unbalance protection if the first level is active; setting the system protection level as a second higher level of phase unbalance protection if the first level is not active; and initiating a motor shutdown if the system protection level is exceeded by the maximum unbalance phase deviation.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-10-14 | 1995-04-15 | 1995-10-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-10-14 | 1999-04-15 | 1999-10-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-10-14 | 2003-04-15 | 2003-10-15 | $7700.00 | Window Closed / Lapsed |