Mr.Dan Posted June 12, 2006 Share Posted June 12, 2006 Does anybody know how to make your own resistors? I need one to slow down my star roller (used a box fan). Link to comment Share on other sites More sharing options...
RUUUUUN Posted June 12, 2006 Share Posted June 12, 2006 Why not just gear it down to the speed you want? Link to comment Share on other sites More sharing options...
al93535 Posted June 13, 2006 Share Posted June 13, 2006 Resistors are cheap as hell, go buy some. Although I have never tried using one on any AC appliance. I think gearing down would be best. But then again, I would advise to buy a 35$ 1/3 HP motor as well. Link to comment Share on other sites More sharing options...
mattcam3 Posted June 13, 2006 Share Posted June 13, 2006 You cannot just use a single resister to slow down an AC fan. There’s a lot of other stuff including the phase that would get messed up. If you really want to make a homemade resister, get a piece of paper and a graphite pencil. Make a dark line on the paper, then measure the resistance w/ a multimeter from different points along the line, the further the two points are from each other (more graphite connecting them) the higher the resistance will be. Another option is to go to home depot or the like, and buy a ceiling fan speed changer. A cheep one will cost about $12. And if all you want is a resister, buy them. They are extremely cheep. Link to comment Share on other sites More sharing options...
justanotherpyro Posted June 13, 2006 Share Posted June 13, 2006 The ceiling fan speed controls supposedly mess up AC motors. They aren't designed to have the electricity flow manipulated like that. A good way to go is 12 volt DC, because they handle it better. Treadmill motors all the way. Link to comment Share on other sites More sharing options...
Mr.Dan Posted June 13, 2006 Author Share Posted June 13, 2006 Where do you even get a tread mill motor without getting a treadmill? Link to comment Share on other sites More sharing options...
Mumbles Posted June 13, 2006 Share Posted June 13, 2006 Junkyard or ebay. Link to comment Share on other sites More sharing options...
mattcam3 Posted June 15, 2006 Share Posted June 15, 2006 The ceiling fan speed controls supposedly mess up AC motors. They aren't designed to have the electricity flow manipulated like that. A good way to go is 12 volt DC, because they handle it better. Treadmill motors all the way. Interesting, I had not heard that before. Do you know why? I was under the impression that ceiling fans were AC. Link to comment Share on other sites More sharing options...
Pont Posted June 16, 2006 Share Posted June 16, 2006 The variable ceiling fan controls do not mess up AC motors. The Variable controller only modifies the AC currents magnitude not its phase. This change in magnitude affects the slip speed of the motor and for a washing machine motor changes the load torque to a less efficient value. Essentially there is a direct relationship between speed, torque and speeed slip of the motor. I really needed a half a page to explain that properly..... Link to comment Share on other sites More sharing options...
Mr.Dan Posted June 17, 2006 Author Share Posted June 17, 2006 resistors are dumb this thread is dumb locked Link to comment Share on other sites More sharing options...
RUUUUUN Posted June 17, 2006 Share Posted June 17, 2006 Mr. Dan, you don't have to visit this forum, please exercise a little self control and not come to this forum, ever. If you can't do that, Frag your comp for Pyrotechnics sake. In short, Zip your howling screamer. Link to comment Share on other sites More sharing options...
marks265 Posted January 15, 2008 Share Posted January 15, 2008 AC motors run at 60 hertz in the USA. These motors are best controlled by frequency inverters which are expensive when bought new. The inverter will increase the hertz to speed up a motor and decrease to slow down. Voltage stays constant and the motor lives to see another day. When using a resistor most motors of any size do not like a voltage drop because they are designed for 120 volts. When this happens things like torque go right out the window as well as run hot and make funny noises. DC motors on the other hand do use a change in voltage to change speed and is much more capable with the right controls and is still pricey. DC motors for years was the best way for speed control until frequency inverters were perfected. With precision, really neat stuff like servo motors with feedback were invented but that is way out of hand for our use. Usually you would want to design the ac motor to run at speed and gear or belt reduce to final drive and is the cheapest most reliable way. I definately agree with Pont. This thread may be old but should have value to someone. I am thinking about building myself a roller as well. I envision a 90VDC gear motor with speed control from EBAY as an ultimate myself! Link to comment Share on other sites More sharing options...
TheSidewinder Posted January 15, 2008 Share Posted January 15, 2008 We got rather off-topic. And old. Good, though obscure, information. And with that, I think it's time to lock this post. M Link to comment Share on other sites More sharing options...
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