Re: [CAD_CAM_EDM_DRO] Re: Why gecko drives don't support DC brushless servo ? do they ?

Generally driving sine waves (via pwm) into the windings should smooth the
cogging of a brushless. You could think of it in the same way as
microstepping, since it's basically the same thing anyway.

On 10/9/06, Jon Elson <elson@...> wrote:
>
> turbulatordude wrote:
>
> >--- In CAD_CAM_EDM_DRO@yahoogroups.com, Steve Blackmore <steve@...>
> wrote:
> >
> >
> >>On Sun, 08 Oct 2006 19:40:36 -0000, you wrote:
> >>
> >>
> >>
> >>>Last week I mentioned some brushless motor airplane motors on this
> >>>page.
> >>>
> >>>
> >>Brushless airplane motors are not a really a good choice. They are
> >>designed for a purpose. They are very coggy at low speeds and overheat
> >>without adequate airflow. You may be able to find a good motor, by
> >>chance or experiment, but you'd be better advised to buy a suitable
> >>motor in the first place and save your wallet/time ;)
> >>
> >>Steve Blackmore
> >>--
> >>
> >>
> >
> >
> >There was some discussion some months ago about optimizing motors by
> >offsetting the armature or brushes or some such to allow the motors to
> >run better at some speed and/or direction.
> >
> >do you know if this is the case with these R/C type motors ?
> >
> >
> The technique involves putting a twist in the armature laminations when
> they
> are installed onto the motor shaft. I don't think it is possible to do
> this without
> completely disassembling the motor. And, this only applies to a DC brush
> motor.
>
> For the same effect on a typical brushless motor, you would probably need
> to
> make new stator laminations, or arrange to (re)install them in the motor
> housing
> with a twist to them. If the motor only has 2 rotor poles, then the
> stator would
> need a 1/6th turn, or 60 degrees, from front to back. I think this
> would play
> hob with the commuation of the motor. (But, maybe it would be very smooth
> and not lose too much torque.)
>
> Jon
>
>
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