Re: [CAD_CAM_EDM_DRO] motor types

From what I recall:

Every motor in your machines will be brushed. Brushless motors are
backwards, they have the magnets on the inside and the coil around the
outside, brushed is magnets outside coils inside (A normal motor). The major
difference is that the brushed motors have brushes connecting the current
supply to the coils as they turn so the rotor has a drag 'needlessly' put on
it. There are different ways of transferring the energy to the coils but
brushes is the cheapest. Brushless motors have a stationary coil so there is
no drag put on the rotor except by the imperfect bearings. Brushless motors
are used when the job is critical or needs doing accurately. Brushless are
much more expensive. Model electric planes (Electric powder prop!) use
brushless motors in place of brushed and that makes the motor worth
something above £100. A servo is a motor that gives feedback of it's
position. In CNC encoders give the feedback to the controller to tell it
where it's made a mistake ect. In model planes the same thing happens but
the feedback is fed straight into the servo's own mini correction system.
For CNC you will use brushless motors. You stick you're encoder on the motor
and hey.... you have a servo. Plug the encoder into your controller and you
have a close loop system, that is the system can report back on itself. You
can miss out on the encoders and have an open loop system, like most stepper
systems.

John

> Okay, now I'm stymied.
> I've got the steppers for the pasma machine,
> but wa looking around for motors for the mill.
>
> Cna someone explain what teh difference between "brushed dc",
> "brushless dc", and "servo" are?
> I know the difference in construction for brushed and brushless,
> but what's optimum for our purposes?
> Is one just a normal electric motor like those that run my machines?
>
> Too much brain expansion for one week...
>
> Weyland
>
>
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