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Jamie Jamie is offline
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Default how to bypass dremel tool internal variable speed control?

Michael A. Terrell wrote:

Claude Desjardins wrote:

wrote:

Just take it apart, I'm pretty sure it's just a "potentiometer"
(variable resistor) so it would only have 3 leads, one from the external
wire to the pot., one from the pot to the motor, and one from the other
external wire to the other lead of the motor.

Cut things off, plug the external leads directly to the motor.


Unfortuantely it doesn't seem that simple. The speed control has what
looks like a some kind of semiconductor/IC (3 leads), a diode, and
maybe a fixed resistor in addition to the slide pot. I don't know if
they're doing pulse width modulation or what.


I doubt they have put a stepper motor in there, they wouldn't sell for
20$ each! -- You still should only have two leads coming out of the
motor. Confirm?




Every Dremel tool I've had apart used a universal motor, and the
speed control was a simple dimmer circuit. This one might be PWM, and
run the motor on DC.

Most of the cordless drills these days use PWM power FeT drivers.

I modified a cordless drill with a mini PIC and Bridge to
perform regulated torque control, auto reverse and then forward
again until maximum torque was no longer peaking. Did this so that
the drill would have a TAP mode in it. I stuck a mini pot on the back
side of the handle to set the torque level.

if his dremel is also cordless, It may also be using it a PWM?
who knows. how ever, with the part count, I'm guessing he's using a
corded unit with a phase control.


--
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