fan alternate voltage max amps

macguyver

I'm needing to upgrade my part cooling fan. Found a fan I'm liking, but it's pulling nearly 3 amps at 12v. I'm running a Duet 3. If I connect an external 12v power source to VOUTLCx, am I correct in assuming it should handle the same 10A it would for VIN(24v)?

fcwilt

@macguyver said in fan alternate voltage max amps:

I'm needing to upgrade my part cooling fan. Found a fan I'm liking, but it's pulling nearly 3 amps at 12v. I'm running a Duet 3. If I connect an external 12v power source to VOUTLCx, am I correct in assuming it should handle the same 10A it would for VIN(24v)?

What board are you using?

What connection are you using for the fan itself?

Frederick

droftarts

@macguyver I think it would be limited by the specification of the MOSFET on the negative/PWM fan pin and/or the rating of the connector (KK are rated for 4A, I think). However, I can't quickly lay my hands on what MOSFET is fitted (I think you have a Mini 5+), and what the limits are.

Ian

dc42

@macguyver is any of OUT0, OUT1 or OUT2 free? If so then I suggest you connect the fan positive wire to your +12V supply, and the fan negative wire to the OUT- pin of one of those ports.

3A is right on the limit for the VOUTLC pin and the Molex KK connector.

I am assuming that the fan you found isn't available in a 24V version.

macguyver

@dc42 Good thing I didn't go with my assumption! Out3 is open so I can use that, just won't get the PWM function. I wish i could find it in a 24v version, best 24v fan I found in this size factor is half the CFM.

https://www.digikey.com/en/products/detail/delta-electronics/BCB0812UHN-TP09/2034820

Phaedrux

Noise
69.3dB(A)
Power (Watts)
27.6 W
RPM
10800 RPM

Dear Lord.

Topher

@dc42 to gain back his PWM, would it be possible to configure lets say OUT7 OUT8 OUT9 outputs to all behave the same allowing the negative leg of each output to be jumped together giving 3x the current handling? (as long as Vin is == his high power fan voltage)

dc42

@macguyver said in fan alternate voltage max amps:

Out3 is open so I can use that, just won't get the PWM function.

All OUT pins support PWM.

dc42

@leckietech said in fan alternate voltage max amps:

@dc42 to gain back his PWM, would it be possible to configure lets say OUT7 OUT8 OUT9 outputs to all behave the same allowing the negative leg of each output to be jumped together giving 3x the current handling? (as long as Vin is == his high power fan voltage)

That wouldn't work, because the PWM on multiple outputs isn't locked together even when they have the PWM set to the same value.

achrn

I don't think you need a high current output on the Duet.

The data sheet linked shows the fan is a four-wire, and specifies that at 0 duty cycle the fan stops. As such, I don't think you need a high-current output at all - the fan can be connected directly to the power supply, and only the PWM (and ground) connected to an output on the duet board - the PWM pin has at least 10K input impedance (diagram on page 8 of the data sheet).

macguyver

@phaedrux I'm not a fan of those numbers either, but the other numbers will hopefully make up for those.

Air Flow
30.2 CFM (0.846m³/min)
Static Pressure
3.675 in H2O (915.4 Pa)

and I don't think i'll need to run it at 100%, at least not all the time. I'll probably try this one first, it's pushing twice the volume as my current fan and should be a drop in replacement for the most part, but I just have a feeling it's still not going to be enough.

https://www.digikey.com/en/products/detail/nmb-technologies-corporation/08028GS-12N-AA-00/7361988

And if that's STILL not enough, i'll have to make a ton of small changes to the printer, but there is this beast.

https://www.mouser.com/ProductDetail/Sanyo-Denki/9BMC24P2G001?qs=YCa%2FAAYMW02fIOwM%2FQgGaA%3D%3D