Patent FR795764A successfully refreshed from Google Patents.
Patent US4856078A successfully refreshed from Google Patents.
US4856078A
Expired / Lapsed
US
⏱️ 0.0 years remaining
DC fan speed control
Assignee: Zenith Electronics LLC
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Filing: 1988-03-23
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Granted: 1989-08-08
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Expires: 2008-03-23
Abstract
Abstract A simple pulse width modulator speed control for a brushless DC "pancake" type fan motor utilizes a type 555 timer for driving a transistor switch, connected in series between the DC voltage supply and the fan motor, at about a 10 Hz rate. The duty cycle of the pulsed output of the timer is controllable by a variable resistor, which in the preferred embodiment comprises a thermistor for controlling the fan speed as a function of temperature. The fan motor is restarted on each cycle of full voltage amplitude pulses and consequently will start under all operating conditions.
Inventors
- 👤 John G. Konopka
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 12:23
CPC Classifications
H; H02; H02P; H02P1/00; H02P1/16; H02P1/18; H02P7/00; H02P7/06; H02P7/18; H02P7/24; H02P7/28; H02P7/285; H02P7/29; Y; Y10; Y10S; Y10S388/00; Y10S388/923; Y10S388/934
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
109 words
A speed control for a DC fan motor comprising: a source of DC voltage; a switch transistor connected in series with said motor and said voltage source; a type 555 timer including an RC circuit coupled to said voltage source for developing a constant amplitude pulsed voltage output; means for operating said switch transistor which said pulsed voltage output; and means for varying the on/off cycle of said timer, said RC circuit including a thermistor for changing the speed of said motor as a function of temperature, said speed control consisting of two capacitors and two resistors in addition to said switch transistor said 555 timer, and said thermistor.
Claim 2
Dependent Claim
109 words
A speed control for a DC fan motor comprising: a source of DC voltage; a switch transistor connected in series with said motor and said voltage source; a type 555 timer including an RC circuit coupled to said voltage source for developing a constant amplitude pulsed voltage output; means for operating said switch transistor which said pulsed voltage output; and means for varying the on/off cycle of said timer, said RC circuit including a thermistor for changing the speed of said motor as a function of temperature, said speed control consisting of two capacitors and two resistors in addition to said switch transistor said 555 timer, and said thermistor.
Claim 3
Dependent Claim
24 words
The speed control of claim 1 wherein said on/off cycle is variable from approximately 30 percent to 90 percent at a 10 Hz rate.
Claim 4
Dependent Claim
101 words
A speed control for a brushless DC fan motor comprising: a source of DC voltage; a switch transistor having a base and an emitter-collector path connected in series with said voltage source and said motor; a type 555 timer coupled to said DC voltage source and to said base of said switch transistor, said timer supplying constant amplitude voltage pulses to said transistor at approximately a 10 Hz rate; an RC circuit coupled to said timer for varying the duty cycle thereof; and a thermistor in said RC circuit for controlling the speed of said motor as a function of temperature.
Claim 5
Dependent Claim
101 words
A speed control for a brushless DC fan motor comprising: a source of DC voltage; a switch transistor having a base and an emitter-collector path connected in series with said voltage source and said motor; a type 555 timer coupled to said DC voltage source and to said base of said switch transistor, said timer supplying constant amplitude voltage pulses to said transistor at approximately a 10 Hz rate; an RC circuit coupled to said timer for varying the duty cycle thereof; and a thermistor in said RC circuit for controlling the speed of said motor as a function of temperature.
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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) | 1992-08-07 | 1993-02-06 | 1993-08-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-08-07 | 1997-02-06 | 1997-08-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-08-07 | 2001-02-06 | 2001-08-08 | $7700.00 | Window Closed / Lapsed |