schiller Posted December 5, 2004 Report Share Posted December 5, 2004 Hi, I dont know much about building circuits and such like but I am trying to adapt some equiptment of mine. It is a device the runs from a 9V alakline battery and powers 2 motors. It is currently controlled by a micro switch but I want to be able to vary the speed of the motors. I found that the 2 motors have a resistance ot 2ohms which should equate to ~10W, I think?Standard potentiometers aren't rated this high and I haven't seen any suitable. What would I need to do to decrease the power through the pot to control the motor speed and what rating pot/components should i use?Thank ou very much for your help :)Schiller. Quote Link to comment Share on other sites More sharing options...
ante Posted December 5, 2004 Report Share Posted December 5, 2004 Hi schiller,Welcome to this forum.If the motors are pulling any load and you want to control the rpm resistors or rheostats is not the best solution. Resistors are not very efficient in a motor circuit and besides the heat losses it is not possible to keep a steady rpm. The best way to do it is PWM (Pulse Width Modulation), there are many ways to set this up: Here is a few: http://www.electronics-lab.com/projects/motor_light/003/index.htmlhttp://www.electronics-lab.com/projects/motor_light/033/index.htmlhttp://www.electronics-lab.com/projects/motor_light/038/index.htmlIf you don Quote Link to comment Share on other sites More sharing options...
audioguru Posted December 6, 2004 Report Share Posted December 6, 2004 Hi Ante,Oh, oh. You posted the Cmos oscillator project that claims to be a PWM motor speed control. :o Quote Link to comment Share on other sites More sharing options...
schiller Posted December 6, 2004 Author Report Share Posted December 6, 2004 Hey, thanks for that Ante. I think i will probably have a go with *33. Just 1 question, that project uses a 6V supply, what is the easiest way of converting it to 9V? Would I have to step down to 6V to power the oscillator and have a direct supploy of 9V to the switch?Cheers :) Quote Link to comment Share on other sites More sharing options...
ante Posted December 6, 2004 Report Share Posted December 6, 2004 Audioguru, Schiller,Yes you are right Audioguru, I Quote Link to comment Share on other sites More sharing options...
audioguru Posted December 6, 2004 Report Share Posted December 6, 2004 Hi Ante,My nasty comments about it got deleted. Quote Link to comment Share on other sites More sharing options...
audioguru Posted December 6, 2004 Report Share Posted December 6, 2004 Hi Ante,My nasty comments about that bad circuit got deleted.I asked the author about it and he said it worked fine for his scooter.People are complaining about it on his site too. Quote Link to comment Share on other sites More sharing options...
ante Posted December 7, 2004 Report Share Posted December 7, 2004 Audioguru,It Quote Link to comment Share on other sites More sharing options...
schiller Posted December 7, 2004 Author Report Share Posted December 7, 2004 No. no, thats fine. It just means I will have to put some time aside to have a good read. Thanks for you help tho guys, I'm sure i'll be back if i need more help :) Quote Link to comment Share on other sites More sharing options...
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