1 Topic by browner87

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Topic: Best way to tap small amounts of power from SD3

Hi all,

I know the x/y stepper motors of the SD3 get really hot, so I got a few 40mm fans that arrived today and I'm wondering how best to wire them in. I know there is a fan over the extruder stepper motor (which I'm replacing because its bearings were DOA - it hurts the ears to listen to) which already has its own motherboard header. No problem there - snip snip, solder solder, shrink-tube shrink-tube, done.

Now, the next 2 fans for the steppers.

Can they solder to the same header? Can that header feed power to all 3 (maybe 4 in future if I get an extruder fan) 40mm fans? Should I splice off of the bed heater wire because it can handle lots of power? Or should I just go the easy/safe way and just stick a 9v battery to the side of the case and wire them to it? I haven't actually tried, but I don't know if a 9v will power 2 12v fans for any length of time and fast enough they don't burn out.

Any suggestions?

P.S. a new power supply with multiple outputs isn't in the near-future plans yet. Eventually I'll be getting a replacement PSU which I'll be able to tap into, but I want these fans installed ASAP to avoid killing my motors - they get way too hot for my comfort (I don't trust my temp gun that says they're 50 Celsius anyways).

2 Reply by grob

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Re: Best way to tap small amounts of power from SD3

Those fans really don't use much power. You should be ok to run those fans off that header, it's just straight out of the 12V so only limited by the track width on the board really. Splice them off the cable wherever it's convenient (aim for spots are where it's not moving / can be taped down).

When you put the extruder fan on, you'll likely want to run that off the g-code controlled fan output so you can have it turned on and off during the print.

Have fun!

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 browner87

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Re: Best way to tap small amounts of power from SD3

Hmmm, I wasn't yet aware that there was a pre-installed header for a gcode controlled fan. Then again, I have yet to see a picture of a solidoodle with the same motherboard as mine. It must be a really new revision, it's got a plexiglass cover and all SMT parts (got it Dec '13). I'll see if I can find that header and maybe run the extruder and X-axis fan from it...

The Y-axis stepper is heat-sinked to the case so it can wait until I get a power supply (probably a couple weeks) then I can run it straight from a 12v source.

Thanks for the tips!

4 Reply by AZERATE

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Re: Best way to tap small amounts of power from SD3

If you recieved your SD new in Dec 2013, you have a Printrboard which has a spot where you can install a header yourself. But just to help you be certain:

AZERATE wrote:
Bookmaker wrote:

http://i.imgur.com/5M8FuMh.jpg

This is a Printrboard Rev-E

ldymox wrote:

http://www.soliforum.com/misc.php?action=pun_attachment&item=5352&download=0

This is a Sang

Printit Mason and Printit Horizon printers
Multiple SD2s- Bulldog XL, E3D v5/v6/Lite6, Volcano, Hobb Goblin, Titan, .9 motor, Lawsy carriages, direct Y drive, fishing line...the list goes on
Filawinder and Filastruder #1870.....worth every penny!

5 Reply by wardjr

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Re: Best way to tap small amounts of power from SD3

Disregard the arrows in the first photo those are the boot jumpers not a fan header.  Just don't want any confusion.

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

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6 Reply by jawhn

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Re: Best way to tap small amounts of power from SD3

browner87 wrote:

... Or should I just go the easy/safe way and just stick a 9v battery to the side of the case and wire them to it? I haven't actually tried, but I don't know if a 9v will power 2 12v fans for any length of time and fast enough they don't burn out. ...

Before you went with a battery, I'd just use a 12V AC adapter. Something with low mA, like ~200mA or so if you can find one. Thrift stores are a great place to pick up one for a buck or two.

A higher "Amp" rating probably wouldn't hurt it, but I lean towards not overpowering things like fans whenever possible.

Something like this:

http://www.americanmusic.com/images/xlarge/13578_x.jpg

Two SD3s - One with Sang, One with Printrboard, Fans on control boards!!! Do this!!!, Dual Glass Beds, Blacklight "EZ Bake Oven" - Improves Ambient Temp, Sketchup, Repetier, Slic3r. Graphic Designer & Makeshift Engineer. Drinks Lots and Lots and Lots of Rum.

7 Reply by grob

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Re: Best way to tap small amounts of power from SD3

[constructive pedantry]

jawhn wrote:

A higher "Amp" rating probably wouldn't hurt it, but I lean towards not overpowering things like fans whenever possible.

You could put a 200mA 12V supply or a 200A 12V supply on one of those fans and they'd take exactly the same amount of power. However, I agree with your tendency to pick a supply with a current rating more appropriate for the load, as this minimises cost & space, and (assuming the supply is over-current protected, which may not be the case with some cheaper smaller ones) minimises damage in the case of a fault. If it's too small though, it will run hotter and less efficiently, and may present a risk in itself. I usually aim for a supply with 50-100% overhead on the load (much like we do using 30A supplies to run SD's), as this usually covers a wide range of quality and uncertainty about the true nature of the load.

Most DC fans have their current draw (0.1A, 100mA for example) written on the label. Add these together, and make sure whatever it's connected to is rated to 50-100% more than this.

A more conservative method would be to use fuses to protect separate circuits - e.g. have individual fuses for the heater, hot-end, steppers (i.e. board) and auxiliaries (e.g. fans) all run off one good quality high-current supply - much like a car, where batteries can deliver in excess of 200A if shorted. Panels for doing this are available from electronics shops; people use them in boats, caravans and excessive car audio setups tongue. This would provide maximum protection from short-circuits and other faults, and probably represent something close to best practice. For these machines, it's probably a little on the extreme side of course, but in the light of recent events on this forum regarding fire risk maybe something we should all be thinking about a bit more.

[/constructive pedantry]

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