stepper motor adjusting

hi all
my printer is set & running BUT!
i have stop in the prints the controler is hot!!!
i ned to adjust the current but dont now how cent find in the web
i use
ps: 12V
ramps 1.4
4 stepper pulolo on the bord
1.7 A stepper 400st
merlin : fm
please help me im lost!!!
thenks
sivan

Aim a fan at the Ramps board

---

_______________________________________
Waitaki 3D Printer

RAMPS requires active cooling with a fan (a 40mm or 50mm fan is usually enough), and you may want to put small heatsinks on the Pololu chips if they haven't already got some. The fan needs to run all the time. You can usually wire a 12V fan to the 12V AUX pins near the PTC fuses.

Note: If your fan doesn't work when you plug it in to those pins, reverse your fan. The connector is not labelled +ve or Gnd, and many fans only work when the voltage is connected the right way round (the fan shouldn't be damaged by plugging it in backwards).

One other note on the fan - if it hits the board from the side of the board rather than the top, that's better for cooling the Mega regulator. It's got some issues if you bump the supply up a bit above 12V.

I have two printers based on RAMPS controllers. Neither has a fan. One of the printers is relatively new with very little use as of yet, but the other has been used extensively for over a year and a half, often printing continuously for days at a time. My RAMPS boards have never overheated.

Every printer is different; some printers require active cooling some do not. I wouldn't install a constantly-on fan except as a last resort after making sure everything was properly calibrated.

The main heat issue on most ramps boards is the stepper controllers. Some of the plug in modules have more copper / better cooling built into them than others. The little heat sinks you stick on come in a wide variety of forms, so does the stick on stuff. Some setups restrict convection air flow more than others. Some people run a lot more power into their motors than others. Some "12V" supplies struggle to get to 11V, others put out 14V under full load. Some people have heated beds that pull a lot of current, others don't use them at all. So yes, there's a lot of variation. There will never be a single one size fits all solution.

A little fan will probably pull < 0.1A off the +12 supply. You can get them for $2. You can get ones that are more quiet for a bit more. The cheap ones aren't that loud compared to the printer it's self. The fan mount is simply an excuse to print something. A properly mounted fan won't hurt your electronics, it will lower their temperature. The current they pull is insignificant compared to the rest of a normal printer. If the OP is correct and he's seeing thermal shut down, it's a cheap fix.

Should you always put a fan here or there? - it's always going to be a "that depends" sort of thing. You can go crazy with fans. Think about the why before you do it just because you can. If it makes sense then of course - do it.

-----------------------

Speaking of the OP:

The current to the motors is set with a pot on the control board. The best way to set it is with a volt meter to measure the voltage. It can be done without one, but it's a major pain. Get a DVM and see where your voltages are set. Once we know that we can help you with setting them *if* they need to be reset. The voltage is most easily measured between ground and the wiper on the pot. Turn off the hot end and heated bed when checking things, it cam make them easier to measure.

Edited 1 time(s). Last edit at 11/10/2013 10:44AM by uncle_bob.

]quote=jbernardis]
I have two printers based on RAMPS controllers. Neither has a fan. One of the printers is relatively new with very little use as of yet, but the other has been used extensively for over a year and a half, often printing continuously for days at a time. My RAMPS boards have never overheated.
Every printer is different; some printers require active cooling some do not. I wouldn't install a constantly-on fan except as a last resort after making sure everything was properly calibrated.[/quote][/color]

Yes, mine worked without issue with no fan connected to cool the chips and Mosfets. However, with a heatbed drawing the current it does, I found the Polyfuse would sometimes shut down (in the summer anyway) so I mounted a fan mostly to keep just the fuse cool.

Edited 1 time(s). Last edit at 11/12/2013 08:11PM by waitaki.

---

_______________________________________
Waitaki 3D Printer

The reliability of any electronic part goes down as it gets hot. Cooling (relatively) expensive electronics with a cheap fan is a very normal thing to do. The parts do have a point where they self protect due to heat. That point is much hotter than you should normally run them. Their MTBF is significantly impacted long before they get anywhere near that point.

The part count on these boards is not very high, they will likely outlast the rest of the printer by a wide margin at a reasonable temperature. Even running hot, they might run for years in a couple of hours a day type of use. It's going to be a law of averages sort of thing. Without a large number of boards in the sample you will have a hard time predicting how long the average is. That makes an exact cost analysis impossible. To me putting on the fan is a pretty easy decision.