# about motor controller



## nj542 (Jun 2, 2008)

Hi,
I've noticed that Curtis motor controller is giving off very high pitch sound when running on low RPMs...

I'm wondering,...does all controllers make a sound like that, or just the Curtis controller(I think that is 144v controller)..

any one using controller other than 144v Curtis???
other brands, other Curtis models??


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## xrotaryguy (Jul 26, 2007)

The Curtis controller switches at a lower, audible frequency while the motor is operating at very low rpm. The controller does this so that it can more accurately monitor current. More specifically, it is protecting against a short circuit condition at low or zero rpm. I don't know whether or not other controllers do this.


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## mattW (Sep 14, 2007)

As far as I know Curtis is the only controller with an audible PWM frequency. You can go with a kelly or zilla at 144V if it bothers you.


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## nutsandvoltsvw (Oct 29, 2007)

I Just ordered a Curtis 1231c-8601 not going to be ready to ship till June 10th... from Electric Vehicles USA for $1420.00 seemed to be a good price but long delivery...does this seem reasonable?


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## Twilly (Jan 22, 2008)

I got mine from EVUSA also, and I think to get the better price, they wait until they can buy a bunch at a time... I think when mine came in, it was with 20 others...

7 days isnt bad...


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