1 Topic by mdrVB6

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Topic: Can I run 4 fans in parallel from a single terminal on the RUMBA?

Hi everyone,

I am wondering if it is okay to run 4 fans in parallel off my RUMBA board from one port (Fan 0)?  I've got 2x 40mm fan on the RUMBA to cool the drivers, then the 40mm extruder heat sink fan and my E3D hot end is in the mail so that will hopefully be added this weekend for another 30mm fan.  I've got a 360 watt PSU with 1/3 ports going to the main board and 2/3 going to the heat bed input, so I've got 120 watts to split between motors, extruder, LEDs, and fans.  I'm not sure what each draws.

Prior to now, I've just had a desk fan pointed at the RUMBA but I got a case printed to protect it that integrates fans.  I plan on making a fairly complex crimped cable for all the fans with multiple JST plugs so everything can be easily unhooked for maintenance.

Alternatively, I could splice some of the fans (probably the RUMBA board fans) into the LED power, which is also always on.  There is also another fan plug on the RUMBA that is for a G-code fan.  I don't ever plan on adding a G-code fan because I have no interest in printing PLA, so I could add the E3D fan to this terminal and input a custom G-code to start it whenever I start a print and then kill it when done.  Does anyone know the command I would enter into my start G-code to do this?  I have heard of doing this, but I'm not sure a typical command would work for the RUMBA in this particular port.

I'm open to any suggestions on the best way to wire all these fans.  Thanks!

SD4 w/ RUMBA, E3D Volcano, all bearings, glass bed

2 Reply by grob (edited by grob 2014-07-16 23:42:49)

  • grob
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Re: Can I run 4 fans in parallel from a single terminal on the RUMBA?

According to the reprap.org's rumba page, the rumba uses one of these mosfets to drive each of the two controlled fan outputs (fan0 and fan1). This is identical to the heater outputs, so it looks like the terminals are similarly capable of running several amps. Fans tend to use in the order of 50-200mA, so you could wire rather a few together and not have to worry about the board.

The E3D fan, board fans, any case cooling, can probably be run continuously by splicing them into the LED power as you suggested, or if you want to switch the E3D fan on and off, perhaps run it off FAN1 (reprap.org site reckons "Could be activated by using Mcode : M42 P8 Sxxx (0 < xxx < 255)").

Save FAN0 for a nozzle fan - you may find you want one for ABS in the future anyway, apparently they help with bridging in certain circumstances, and this is the one that slic3r will turn on and off.

Up to you, have fun with the RUMBA, I'm totally jealous. smile

SD3. Mk2b + glass, heated enclosure, GT2 belts, direct drive y shaft, linear bearings, bowden-feed E3D v5 w/ 0.9° stepper
Smoothieboard via Octoprint on RPi

3 Reply by mdrVB6

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Re: Can I run 4 fans in parallel from a single terminal on the RUMBA?

Ya, I figured it wouldn't be a problem.  At 200ma each I should be fine to put 4 on there.  I think I will put the 2 board fans on the terminal since they need to be removed when I lift the cover and the extruder and E3D fans onto the screw terminal since they won't move as much. 

And yes, the RUMBA is awesome.  I sprung the money for it when I looked at all the posts of people struggling to upload firmware, add fans, add a controller, or do much of anything to the sang or printrboards.  With the RUMBA, I can practically plug and play to upload firmware and its got a port for everything.  It's just very easy to use.  I have written a draft of the complete install that I want to eventually add to the wiki.  If you've got the money, get a RUMBA.  You won't regret it.

SD4 w/ RUMBA, E3D Volcano, all bearings, glass bed

4 Reply by wardjr

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Re: Can I run 4 fans in parallel from a single terminal on the RUMBA?

Glad your happy with your Rumba.  The G-code fan is awesome for ABS when you have small perimeters.  I have also found it useful for increased speeds and can fairly successfully bridge 150 mm's using the fan.  As far as all of your other fans there is no problem running 4 off of either of the fan out puts.  Do all of your fans turn on/off automatically?  They should if you have the correct firmware.  That's probably my favorite feature "Ah, Silence" when it's not printing.  I didn't realize how loud those fans where until I didn't have to listen to them smile

Printit Industries Model 8.10 fully enclosed CoreXY, Chamber heat
3-SD3's & a Workbench all fully enclosed, RH-Slic3r Win7pro, E3D V6, Volcano & Cyclops Hot End
SSR/500W AC Heated Glass Bed, Linear bearings on SS rods. Direct Drive Y-axis, BulldogXL
Thanks to all for your contributions

wardjr's Website

5 Reply by grob

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Re: Can I run 4 fans in parallel from a single terminal on the RUMBA?

RUMBA's on the list for printer #2 smile

SD3. Mk2b + glass, heated enclosure, GT2 belts, direct drive y shaft, linear bearings, bowden-feed E3D v5 w/ 0.9° stepper
Smoothieboard via Octoprint on RPi

6 Reply by mdrVB6

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Re: Can I run 4 fans in parallel from a single terminal on the RUMBA?

Hmm, my extruder fan that I'm running out of the Fan 0 terminal does not turn off automatically.  I will take a look into my firmware when I do the E3D upgrade, hopefully this weekend.  That would be nice to have those turn off.  However, my PSU has an always on fan that just about drowns out the smaller fans so I don't think I would get to enjoy the quiet anyway.

SD4 w/ RUMBA, E3D Volcano, all bearings, glass bed