Voltage decreases after putting a fan into the fan port

[K3K5]

Hello,

i have a 24V fan wich should be controlled by the temperature, but when the temperature 45° reached the fan doesnt spin.
Here are the config lines:

First the lines from the config.json: "fans":[{"value":0,"inverted":false,"frequency":500,"thermostatic":true,"heaters":[1],"trigger_temperature":45},{"value":0,"inverted":false,"frequency":500,"thermostatic":false,"heaters":[1],"trigger_temperature":45}]

And here the lines from the config.g: ; Fans
M106 P1 S1 F500 H1 T45 ; Set fan 0 value, PWM signal inversion and frequency. Thermostatic control is turned on
M106 P0 S0 F500 H-1 ; Set fan 1 value, PWM signal inversion and frequency. Thermostatic control is turned off

The temp controlled fan is pushed into fan 1 and the other fan in fan 2

Another fact is that the voltage decreases when i plug in the fan, before there are 24V and if the fan is plugged in there are only 5,8V.

I hope you guys can help me...thanks

[SIam]

did you use a turbine what happens when you connect the fan directly to 24 V? have you try to lower / upper the pwm frequency

[K3K5]

@SIam no a normal 40x40x10 24V Sunon fan...if i connect the fan directly to 24V it runs normaly

[SIam]

and if you lower the pwm frequency of this fan to f100

[K3K5]

@SIam i try it out tomorrow

[A Former User]

Where are you measuring this? There could be some voltage drop over the switching FET, but 5v is more than I'd expect. Are you measuring when the output is set to 100% if not your meter may struggle getting an accurate reading as well.

[K3K5]

@bearer i measure the 5,8V at the fan connection but the cable is not the problem because when the fan is connected to the always on fan port i can measure the 24V at the fan

[K3K5]

@SIam doesnt changed anything tried freq 10000 and freq 100 still only 5,8V and no spinning fan

[SIam]

please try to connect the fan to a other pwm output and report the result

[K3K5]

@SIam the next Port worked, so is the first one broke ?

[SIam]

it look like that the mosfet from fan 0 is faulty

[Quattro]

Are you running a 24V fan on 5V? It is going to be slow. I connected mine to E1 heater on the Duet.

[K3K5]

@SIam can i replace it ?`its the mosfet from fan1

[K3K5]

@Quattro no the voltage drops to 5,8V when the fan is connected and if i remove the fan the voltage is 24V

[A Former User]

@K3K5 said in Voltage decreases after putting a fan into the fan port:

can i replace it ?

https://github.com/T3P3/Duet/tree/master/Duet2 schematics are available