So after adding a 6mm aluminum heat spreader to my rostock max I decided a BIG 18v psu would help me get it to temp faster.... Totally forgot that this also feeds far to much juice to my fans and may explain why i have killed a small stack... Option 1) run two psu.... PITA..... Option 2) Run two 12v dc fans in series from the 18v supply..... I would rather go with option two as I feel more peek cooling with help with with my poor retractions and also saves having to install a second 12v supply... Any one see a downfall to running with option 2?
Perhaps another option would be to use a 12Volt regulator, 7812 or similar (on a heatsink) to drive your fans from the 18Volt supply. Tweakie.
Thanks for the idea @Tweakie and I was just about to head to the shop to pick some parts up but using a regulator would negate any fan speed adjustment I have as it would hold the fans at 12 regardless of the power input. OR should a peek fan be on full blast all the time?
Or by feeding the 12v into the rambo from the reg it should then adjust the fan speed via PWM on the Rambo ?
I believe the 7812 IC is only rated for 1.5 amps with a heat sink, if you require more amps look at the LM350t It is rated at 3-5 amps I believe and is adjustable
I would run the fan at max speed all the time. I can't see why you would want to reduce it, unless the noise is an issue but than the noise from the cutting will be an issue too. LOL
JustinTime - You are right about the noise from cutting but the noise from squirting hot plastic is more of a "Sploosh" or a "Splat" as to a "RIP,WHINE or SCRAPE" noise from a mechanical cutter. So Fan noise can be a real annoyance when using a 3d-printer. Bob
If you are simply running the fans and want variable speed then just use the LM317 and adjust your pot for speed control Simple, easy, cheep
