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Unread 21-05-2014, 16:15
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Paul Copioli Paul Copioli is offline
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Re: motor Ke and Kt Quiz

So, for most small, high Flux DC motors there is this phenomenon called magnetic field saturation. It happens when the permanent magnet doesn't have enough field strength to drive the high amount of Flux through the moving parts of the motor. I am simplifying here to try to keep it short.

The bottom line is that at high current (aka, near stall), the magnetic field saturates producing less actual torque than ideal and this is one of the reasons for the difference between Kt and Ke.

However, it is not the only difference. This can really only be found with motor testing.
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In full disclosure I am the President of VEX Robotics, a division of Innovation First International.