24v fan question
Hello.
I am wondering if there are possible to use signal and ground from prusa einsy rambo bord and attach fan power directly to 24v output from power supply?
I have read on a raspberry forum that they manage to do this on a raspberry pi. So my question is if it safe to test. Or get ground to much power back and Bord can't handle it?
Best Answer by Patrick McNamara:
Without further modification, it would be risky. The fan driver circuit has a red LED driven by the same MOSFET that drives the fan, so you have visual indication the fan is on. I am assuming the Prusa Einsy has these LEDs. Running a fan from 24V would reverse bias this diode at 19V. It may, or may not breakdown at this voltage. If it did, you would dump 24V into the Einsy VCC and very likely release the magic smoke from multiple parts.
Now, if you removed the indicator LEDs on the fan circuit, then yes, you could run the fans from 24V and control them from the Einsy. The driver MOSFET is rated for 42V drain-to-source and 42V drain-to-gate.
RE: 24v fan question
Without further modification, it would be risky. The fan driver circuit has a red LED driven by the same MOSFET that drives the fan, so you have visual indication the fan is on. I am assuming the Prusa Einsy has these LEDs. Running a fan from 24V would reverse bias this diode at 19V. It may, or may not breakdown at this voltage. If it did, you would dump 24V into the Einsy VCC and very likely release the magic smoke from multiple parts.
Now, if you removed the indicator LEDs on the fan circuit, then yes, you could run the fans from 24V and control them from the Einsy. The driver MOSFET is rated for 42V drain-to-source and 42V drain-to-gate.
RE: 24v fan question
Thanks a lot for all this information. i am going to check for this led you talking about. yes. 24v for a led is much for a led 😀