A few questions, now that my Mini is(almost) working.

  1. Do i need to power the FET-IN and the Main power connectors? Do they need to be separate power supplies? Can a 12V and 24V supply be used? 12V for the heaters, and 24V for the motors?

  2. Can i drive a fan from the 2.6 and/or 2.4 pins(the MOSFET 3 and 4 headers) Do these pins support PWM, and can they supply enough current for a 12V 30mm fan?

“Chapman Baetzel”

Ray Kholodovsky (Cohesion3D) February 20, 2018 19:13

  1. You do have to provide power to both terminals, you can use the same psu and run 2 sets of wires.

  2. Fet3 and 4 are designed for fans yes. A normal 30 or 40mm fan is fine, say up to 100-150mA.

Chapman Baetzel February 20, 2018 19:36

Excellent. will FET3 and 4 put out 12V if the main supply is 24V?

Ray Kholodovsky (Cohesion3D) February 20, 2018 20:00

Nope, that’s not how an N Channel FET works. It just connects to ground when it’s on. Get a separate 12v PSU or a 24v –> 12v converter and power the + of the fan there. Then connect the - of the fan to the center pin of those FET3/ 4 headers.

And finally your 2 PSU’s will need to have a common ground connection.

Chapman Baetzel February 20, 2018 20:31

that sounds like way too much work to run 12V fans. I’ll just buy 24V fans and swap them in. I say ‘them’ but that printer only has 1 on the e3d hotend. I thought about adding one for the controller itself, but cooling hasn’t really been an issue.

Chapman Baetzel February 21, 2018 16:11

ok so just to recap how i should go about converting to 24V. 1. Replace bed and hotend heaters with 24V units. Replace fans with 24V fans, + to Vin, - to MOSFET pin. Should I expect to adjust my driver current?

Ray Kholodovsky (Cohesion3D) February 21, 2018 16:15

Since you said they were getting hot you might want to lower the current a little bit (small hole in the driver bottom edge, turn the pot counterclockwise a little bit) but that’s a general thing. Motors will perform better at 24v but current will be the same.

Chapman Baetzel February 21, 2018 16:52

the current isn’t digitally controlled? I know i saw a setting for that in the smoothie config.

Ray Kholodovsky (Cohesion3D) February 21, 2018 16:53

Yes, that’s because we kept the stock smoothieboard config file, but C3D/ Stepstick drivers don’t have that option.

Chapman Baetzel February 21, 2018 18:03

alrightey then. good to know. thanx

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