US5777897A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for optimizing the rotational speed of cooling fans
Assignee: NAVY UNITED STATES NAVY, Secretary of
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Filing: 1996-11-26
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Granted: 1998-07-07
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Expires: 2016-11-26
Abstract
Abstract A method for controlling cooling fans for variable electrical loads. A cooller monitors cooling fan output, ambient temperature and the electrical load. The controller then matches the fan speed and resulting cooling to the existing electrical load and ambient temperature. As a consequence, fan speed is maintained at a minimum necessary to sustain appropriate cooling levels. This minimizes the generation of structureborne and airflow noise.
Inventors
- 👤 Paul J. Giorgio
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 02:38
CPC Classifications
F; F24; F24F; F24F13/00; F24F13/24; F24F11/00; F24F11/70; F24F11/72; F24F11/74; F24F11/77; Y; Y02; Y02B; Y02B30/00; Y02B30/70
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
72 words
A method for controlling the temperature within an electrical device disposed in an environment having an ambient temperature by directing air past the electrical device, said method comprising the steps of: monitoring the electrical load of the electrical device; monitoring the ambient temperature; monitoring the air flow past the electrical device; and adjusting the air flow past the electrical device in response to the monitored electrical load, ambient temperature and air flow.
Claim 2
Independent Claim
72 words
A method for controlling the temperature within an electrical device disposed in an environment having an ambient temperature by directing air past the electrical device, said method comprising the steps of: monitoring the electrical load of the electrical device; monitoring the ambient temperature; monitoring the air flow past the electrical device; and adjusting the air flow past the electrical device in response to the monitored electrical load, ambient temperature and air flow.
Claim 3
Dependent Claim
41 words
A method as recited in claim 1 wherein the air flow is generated by at least one variable speed fan and said step of adjusting the air flow includes adjusting the energization level. to the at least one variable speed fan.
Claim 4
Dependent Claim
46 words
A method as recited in claim 2 wherein the electrical load is constituted by a variable load energized by a power supply in response to a load control signal and said step of monitoring the electrical load includes measuring the value of the load control signal.
Claim 5
Dependent Claim
46 words
A method as recited in claim 1 wherein the electrical load is; constituted by a variable load energized by a power supply in response to a load control signal and said step of monitoring the electrical load includes measuring the value of the load control signal.
Claim 6
Dependent Claim
33 words
A method as recited in claim 2 wherein said method additionally comprises the steps of: sampling at least one of the monitored electrical load, ambient temperature and air flow; and saving the sample.
Claim 7
Independent Claim
130 words
A method for controlling the speed of at least one variable speed cooling fan that directs cooling air past an electrical device including a variable electrical load energized by a switching power supply and operated in an environment with a variable ambient temperature, said method comprising the steps of: monitoring the power being coupled from the switching power supply to the electrical load; monitoring the ambient temperature; monitoring the speed of the at least one fan; generating a fan speed set point control signal in response to the monitoring of the power and ambient temperature; and adjusting the fan speed in response to the fan speed set point signal and the monitored fan speed to maintain an appropriate cooling level in response to variations of the power and ambient temperature.
Claim 8
Independent Claim
130 words
A method for controlling the speed of at least one variable speed cooling fan that directs cooling air past an electrical device including a variable electrical load energized by a switching power supply and operated in an environment with a variable ambient temperature, said method comprising the steps of: monitoring the power being coupled from the switching power supply to the electrical load; monitoring the ambient temperature; monitoring the speed of the at least one fan; generating a fan speed set point control signal in response to the monitoring of the power and ambient temperature; and adjusting the fan speed in response to the fan speed set point signal and the monitored fan speed to maintain an appropriate cooling level in response to variations of the power and ambient temperature.
Claim 9
Dependent Claim
37 words
A method as recited in claim 6 wherein the switching power supply operates in response to a pulse-width modulated control signal and said power monitoring step includes measuring the duty cycle of the pulse-width modulated control signal.
Claim 10
Dependent Claim
36 words
A method as recited in claim 6 wherein the at least one variable speed fan includes tachometer means for generating a signal indicating fan speed and said fan speed monitoring step includes measuring the tachometer signal.
Claim 11
Dependent Claim
37 words
A method as recited in claim 8 wherein the switching power supply operates in response to a pulse-width modulated control signal and said power monitoring step includes measuring the duty cycle of the pulse-width modulated control signal.
Claim 12
Dependent Claim
33 words
A method as recited in claim 9 wherein said method additionally comprises the steps of: sampling at least one of the monitored electrical load, ambient temperature and fan speed; and saving the sample.
Claim 13
Independent Claim
189 words
A method for controlling the temperature within a digital computer having a chassis located in an environment having an ambient temperature, said computer chassis enclosing a switching power supply, at least one circuit card that is a variable electrical load device energized by the power supply, control means for generating a pulse-width modulated power control signal for controlling the energization of the power supply in response to a load demand and at least one cooling fan having a speed dependent upon the voltage applied to the input thereof, said method comprising the steps of: initializing the system by energizing the fan with a maximum speed value for a fan speed set point; retrieving one of a predetermined set of first control signal values based upon the level of the power supplied by the switching power supply; retrieving one of a predetermined set of second control signal values based upon the measured ambient temperature; combining the first and second control signal values and the fan speed set point to establish an updated fan speed set point; and adjusting the fan speed to correspond to the updated fan speed set point.
Claim 14
Independent Claim
189 words
A method for controlling the temperature within a digital computer having a chassis located in an environment having an ambient temperature, said computer chassis enclosing a switching power supply, at least one circuit card that is a variable electrical load device energized by the power supply, control means for generating a pulse-width modulated power control signal for controlling the energization of the power supply in response to a load demand and at least one cooling fan having a speed dependent upon the voltage applied to the input thereof, said method comprising the steps of: initializing the system by energizing the fan with a maximum speed value for a fan speed set point; retrieving one of a predetermined set of first control signal values based upon the level of the power supplied by the switching power supply; retrieving one of a predetermined set of second control signal values based upon the measured ambient temperature; combining the first and second control signal values and the fan speed set point to establish an updated fan speed set point; and adjusting the fan speed to correspond to the updated fan speed set point.
Claim 15
Dependent Claim
21 words
A method as recited in claim 11 wherein said retrieval steps, said combining step and said adjusting step are performed iteratively.
Claim 16
Dependent Claim
78 words
A method as recited in claim 12 implemented in a microcontroller, said method additionally comprising the step of storing a table of the first control signal values and said step of retrieving the first control signal value includes: measuring the duty cycle of the pulse-width modulated power control signal; converting the measurement of the duty cycle to a table address; and retrieving, as the selected first control signal value, the contents of the table at the table address.
Claim 17
Dependent Claim
66 words
A method as recited in claim 13 additionally comprising the step of storing a table of the second control signal values wherein said step of retrieving the second control signal value includes: obtaining a digital representation of the ambient temperature; converting the digital representation to a table address; and retrieving, as the selected second control signal value, the contents of the table at the table address.
Claim 18
Dependent Claim
36 words
A method as recited in claim 14 wherein the table of second control signal values includes positive and negative values and the step of combining the first and second values includes the summation of those values.
Claim 19
Dependent Claim
72 words
A method as recited in claim 12 implemented in a microcontroller, said method additionally comprising the step of storing a table of the second control signal values and said step of retrieving the second control signal value includes: obtaining a digital representation of the ambient temperature; converting the digital representation to a table address; and retrieving, as the selected second control signal value, the contents of the table at the table address.
Claim 20
Dependent Claim
36 words
A method as recited in claim 16 wherein the table of second control signal values includes positive and negative values and the step of combining the first and second values includes the summation of those values.
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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) | 2001-07-06 | 2002-01-05 | 2002-07-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-07-06 | 2006-01-05 | 2006-07-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-07-06 | 2010-01-05 | 2010-07-07 | $7700.00 | Window Closed / Lapsed |