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Function detection method of PWM speed regulating cooling fan without external PWM control signal
- Categories:Technology
- Author:rain
- Origin:capital
- Time of issue:2021-02-25 11:06
- Views:
(Summary description)Generally, the DC fan with PWM speed regulation function is 4-wire, and also has 3-wire speed regulation fan. The general situation is as follows:
Function detection method of PWM speed regulating cooling fan without external PWM control signal
(Summary description)Generally, the DC fan with PWM speed regulation function is 4-wire, and also has 3-wire speed regulation fan. The general situation is as follows:
- Categories:Technology
- Author:rain
- Origin:capital
- Time of issue:2021-02-25 11:06
- Views:
Generally, the DC fan with PWM speed regulation function is 4-wire, and also has 3-wire speed regulation fan. The general situation is as follows:
1. Four wire fan: positive, negative, FG speed measurement, PWM speed regulation
2. Four wire fan: positive pole, negative pole, RD alarm, PWM speed regulation
3. Three wire fan: positive pole, negative pole, PWM speed regulation
There are three modes of PWM speed regulation
1. When the duty cycle is 0%, the cooling fan stops - high speed fan is a common mode.
2. When the duty cycle is 0%, the fan runs at low speed.
3. When the duty cycle is 0%, the fan runs at full speed - this mode is rare.
In the case of only DC power supply, without PWM control signal, how to quickly determine the fan PWM speed regulation function?
The signal line combination of cooling fan is as follows:
1. Positive pole, negative pole, FG speed measurement signal, PWM speed regulation.
——Test method:
(1) The positive and negative electrodes, namely the red and black wires, are connected to the DC power supply.
(2) After the cooling fan runs at full speed.
(3) The other two speed measurement and speed control leads are short circuited, generally the yellow line and the blue line
2. Positive pole, negative pole, RD alarm signal, PWM speed regulation
——Test method:
(1) Connect the positive and negative pole, namely the red and black wire, to the DC power supply
(2) After the cooling fan runs at full speed
(3) The other two lines of speed measurement and speed control lead short, generally white line and blue line
---Phenomenon: A: fan running at low speed:
---Judgment: Rd alarm signal and PWM speed control signal are normal, when PWM speed control mode is 0%, the fan runs at low speed.
---Phenomenon: B: the fan stops and starts repeatedly
---Judgment: the RD alarm signal and PWM speed control signal are normal, and the fan stops when the PWM speed control mode is 0%.
3. Positive pole, negative pole, PWM speed regulation
——Test method:
(1) The positive and negative electrodes, namely the red and black wires, are connected to the DC power supply.
(2) After the fan runs at full speed.
(3) The PWM speed regulating line is connected to the negative pole of the power supply
---Phenomenon: A: the cooling fan runs at a low speed.
---Judgment: the PWM is normal and the fan runs at low speed when the PWM speed regulation mode is 0%.
---Phenomenon: B: the fan stops.
---Judgment: the PWM is normal and the fan stops when the PWM speed regulation mode is 0%.
---Phenomenon: the fan speed is reduced.
---Judgment: the functions of PWM and FG signals are normal.
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