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Need help with a potentiometer for speed control?
Okay! I do not get it! I'm building a diy turntable, and I'm trying to use a potentiometer to control the motor that spins the turntable. I've tried a 100k ohm pot, 10k ohm pot, and a 1k ohm pot. They seem to barely work. I have to turn them all the way up for them to work. And even then it doesnt control the speed, they just turn on. I don't know if theyre too big or not. I'm using an input of 5.1v .7a (cell phone charger) and a 5v motor that i got from radioshack. Also my other problem is that everytime the pots do make it turn on, they make a bright light and start smoking. Its burning them and i have no idea why. If the pots are too big for it then why is it burnin them? They shouldnt be hurt by the little power anyways? Please help! Thanks alot!
3 Answers
- ?Lv 78 years agoFavorite Answer
Potentiometers have a wattage rating. You are probably using volume control pots rated at 1/4 watt or 1/2 watt. If your charger spins the motor at high speed (probably way too high) then it is putting about 3.6 watts through the thing - smoke!!!
And it is unlikely that a 5 volt motor from radio shack can turn a turntable without gearing or one or more small pulleys driving large pulley belt drives - most of what the sell is high speed (5000 rpm or more) and if you just try to slow them down with low voltage, they have no power at all.
- RickLv 78 years ago
A small pot won't work, because the resistance is too large and the power rating is too small. You could use a pot to control the voltage to a power amplifier that could drive the motor.
