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Old Apr 04, 2007, 02:27 PM
IBCrazy is offline
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Engineer for Christ
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Amherst, VA
Joined Jun 2006
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The result

To test my new motor, I clamped the endbell in a vice and hooked the leads up to my speed control. I made an infra red tachometer from a fairchild semiconductor QRB1114 Emitter/Collector pair and a couple of resistors.

I placed two pieces of non reflective electrical tape on the can and set my multi tester for frequency. Upon revving the engine up to half throttle, thelectrical tape ripped free. So I then tried again, and it ripped off yet another time. So I then went to my favorite tape, Tyvek, which held just fine.

My multi tester showed 1.26 kHz. Which meant it was seeing tape 1260 times a second! That means my motor was spinning 630 revolutions per second, or 36,000 rpm! At 12 volts, this means the motor is 3000 kv. Not bad.
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