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Old 07-24-10, 05:43 PM   #8
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Originally Posted by Daox View Post
I think you have some things mixed up. Running at a higher voltage does not increase heat. Amperage is what creates heat. Going to a higher voltage allows more power at the same amperage. So, you can either get more power for the same heat generated, or the same power for less heat generated. Going too high over the rated voltage can be a problem and your brushes may spark and wear out faster. Of course, that all depends on the design of the motor. Many of the electric car guys are running their 24-36V forklift motors at 72, 96, even 144 volts without problems.
I'm not mixed up, just ignorant (grin). I was analogizing from ac motors, where doubling the voltage will cause much heat and rapid loss of the magic smoke. I know volts x amps = watts = horsepower, so I can see where for instance 12 volts at 30 amps would equal 24 volts at 15 amps, but I've never thought about why there are more rpms at 24 volts than 12. Does anyone have an explanation of why this works?
I have a dim notion regarding the relationship between rpms and torque, so I guess I need to go back to school on this part of the plan. I have been trying to go with 12 volts because the paper amp hours matches what I need, and I can fit two batteries easily, but three or more gets dicey. I would have thought there was some downside to higher voltages, or we all would be running RC car motors at 150 volts. This may be a very large question, but what am I missing?
toolingjim (Just a guy who likes to build stuff)
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