fan controller

gmoney · Posted: Sun Mar 13, 2005 2:05 am Post subject:

dang... me and my lack of wiring/electrical knowlegde... so ohms is equal to what times wat ? ...

^^ thats so i can get the correct ohm rated rheostat...

tanks mayne... wut if i kept running this fan with it rite now in the meantime.. till i get to the store tomorrow? wont lite up in a ball of fire will it?
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Noxide · Posted: Sun Mar 13, 2005 3:34 am Post subject:

Hey 2old, I just made one of those for my tornado fan today!
Its a 25-Ohm Rheostat from Radioshack.
3 watt wirewound variable resistor +/-20% tolerance
sliding noise <47mV
total rotation 300 degrees +/-5 degrees
Works really good! no probs.

Noxide · Posted: Sun Mar 13, 2005 3:45 am Post subject:

oh also keep an eye on it kuz it gets kind hot. the lower the fan speed, the more resistance, the more heat. im going to try putting a RAM heatsing on it to see if i can disanticipate some heat.( the small kind that has the adhesive) I'll let yall know what happens.

gmoney · Posted: Sun Mar 13, 2005 3:49 am Post subject:

yeah noxide ur rite.... i noticed this as well... kinda worried cuz this is basically the wrong rheobus for the duty... i will get back to u guys later with the fan wattage and voltage
_________________
I finally got an award=OFFICIAL ROCKSTEADY AWARD and then one time... at tweaknews dene gave me a A+++++++....
and then...
i got a couple josh awards too
an' den one of those too -->... Ж award

2old2care · Posted: Sun Mar 13, 2005 2:31 pm Post subject:

yep...the resistance (ohms) of the pot is kind of important...a typical 80mm fan draws about 100 to 150 ma @ full load. So that 25 ohm pot will only slow it a little where a 100 or 200 ohm will slow it pretty well. If you get over say....1000 ohms it'll just become an on off switch.
Your tornado fan is different...draws quite a bit more current and may get into the 3 watts rating, which will get pretty hot.

ohms law.... amps * ohms = volts or Volts / amps =ohms or volts / ohms = amps

Power law....watts = amps * volts

remember...the resistance (pot) must be in series with the load. Like the picture.
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