FAN Mosfet broken, when PWM still works?
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Hey community,
Are my fan mosfets broken when PWM still works? I changed from a 5V PWM axial FAN, to a 24V radial FAN. I use a 24V power supply.
But now I'am unable to switch off the fan anymore, only changing the rpm is possible. I changed it back for testing and in pmw mode i still can use the complete rpm range. The fan is connected to the - pin of FAN1 (or FAN0 for testing) and VIN i cached up at the 5V,VIN,VOUT pinout, because i still set the jumper to 5V because auf the hotend fan. I hope my description is not to confusing. -
Back again,
I tried little more, so i realized that the mosfets are in fine condition. I unplugged all fans and switched the jumper back to vin = vinfan. In this configuration i could fully throttle down the fan. So switched back again and measured the voltage between VIN and - pin of FAN1. In this case the minimal voltage is 18V. So this means, that the here descriped method "Mixed-voltage setups are not directly supported on the Duet 2 WiFi/Ethernet, but the Duet switches the fans' connections to ground, so you may be able to connect each fan's positive side to the appropriate voltage and its negative side to the appropriate pin on the Duet. Each controlled fan can be configured in firmware as a gcode controlled fan or as a thermostatically-controlled fan." don't work for me. The circuit must work different so that only a the amount of input voltage (here delta of 5 V) will be reduced, because with an Input of 5V (using a plus pin of a fan) the mosfed reduce the voltage down to 0V, how expected.
Do anybody also has a mixed voltage setup and give me some advise how to solve my problem? Didn't found a 5V radial fan so far.
greetings Kane
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Sorry for my self talk but I solved my problem. To run am mix of 5V and 24V fans i used the following solution.
- Set the "V FAN" jumper to the V_FAN;VIN position
- Connect the 24V fans normaly
- Connect the black alias ground wire to the minus pin of the chosen fan port
!Do not connect the red alias puls wire to the fan port, with great probability you will destroy our fan and/or the board - Connect the red wire instead to the free 5V pin of the before described "V FAN" pinout area
Now you are able to control all fans from full power to switch off
Maybe a mod can take my description and put it into the wiki, maybe its more easy to find there
Thread closed
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@Kane said in FAN Mosfet broken, when PWM still works?:
Maybe a mod can take my description and put it into the wiki, maybe its more easy to find there
It's already part of the fan wiki. Just substitute 12v for 5v.
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I've added this to make it clearer: https://duet3d.dozuki.com/Wiki/Connecting_and_configuring_fans#Section_Using_fans_with_mixed_voltages
