Cooling fan dying

jroh · 29 Dec 2017, 16:12

Hi,

Could anyone advise why cooling fan for always on become out of order only after using around 2~3 minutes. I wasted 3 fans continuously in a short time and trying to find reason but not easy with my short knowledge on electronics.

Had checked

voltage : 24v, the same as duetwifi
Fan Current : 0.1A (made by Pengda technology)
I extended around 1 meter with 1.5mm diameter wire to the cooling fan wire(around 1.2mm diameter)

I wonder whether there flows over-current due to wider wire extended?
or The fan which has 0.1A is not suitable to Duetwifi?
or Did I miss any of current setting?

Would appreciate for help.

Thanks. / JR OH

kazolar · 29 Dec 2017, 20:36

so the fan dies and stops functioning? As a result it won't spin anymore? If so, I would look for short to ground somewhere – the amount of current is pretty small, so it shouldn't be an issue.

dc42 · 30 Dec 2017, 09:49

Check that there is nothing mechanical that is adding friction to the rotation. In particular, if the fan is screwed to something and the screw holes are not aligned correctly, the screws can distort the fan housing so that the blades rub against it.

jroh · 30 Dec 2017, 13:00

Thanks for advise and I now very suspect whether I misunderstand very basic thing of voltage. I connected 24volt fan to duetwifi always-on pin instead power supply as I had thought duetwifi board supply 24v DC. But searching the webs more carefully it seems Duetwifi supply 5volt for fan. Appreciate anybody confirm the supply voltage.

In the meantime, blower fan is working very well which is same voltage of 24volt and same maker, also my another smaller cooling fans which are also 24volt are working well connected at "always-on" pin. why only 50mm cooling fans are becomes out of order while others working well. This facts made me complex indeed but the other hand I feel satisfied it proves "short to ground" is not happens on the board.

Now I guess there should be over-current to the fan in order to supply Watt with very small voltage. The cooling fans had exactly worked around 2~3minutes and dead which means some extent of Watt was delivered to the fan for 2~3minutes and it makes current over-flow. If my guess is right, it means the blower fan and other smaller cooling fans are also dangerous to be dead unless I do not connect to the power supply directly which supply 24 volt.

Still in a complex as I cannot get spare fan due to holiday and just guess. HAHAHA.

Please forgive my poor knowledge and also appreciate for helps.

Thanks.

dc42 · 30 Dec 2017, 13:34

The fan voltage selection jumper has two positions. One provides 5V to the fans. The other provides VIN to the fans, where VIN is the voltage you supply from your PSU to the VIN terminal block. All fan outputs get the same voltage.

jroh · 30 Dec 2017, 16:57

@David

Thanks your advise and tested the voltages with multimeter as follows.

Voltage when Jumper header on VIN : 28.3 / 28.3 / 28.3 / 15.6 / 0 (always-on / always-on / PWM0 / PWM1 / PWM2)
voltage when jumper header on 5V : 5.6 / 5.6 / 5.6 / 3.2 / 0
voltage from PSU : 28.3 (It should be 24volt but figures on multimeter 28.3)

Now I understand my PSU supplies some high voltage different from rated voltage and it made the fan out of order. In this case what can I do?

I think one option is just use 5Volt fan OR change PSU. Any other options?

In the meantime, can you advise why PWM2 on Duetwifi and all 5 PWM pins on DUEX5 shows 0 voltage, and shows 15.6volt on PWM1 on Duetwifi? PWM voltages varies depend on G-command in config.g file?

Thanks.