Re: Ordinary AC motors & position control

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "maxnc15" <kirk_fraser@...> wrote:

>
> I'm asking for some basic knowledge. I've seen some motors that
> normally spin free lock up pretty solid on a position by use of
> a "dither" frequency to equalize both directions of rotation. Slight
> adjustments can move the motor one way or the other. Now can this
> principle be applied to ordinary AC motors? I understand it works with
> DC motors.
>
> If not, is there a way to easily convert an AC motor to DC?
>
> The reason I ask is new AC motors can be inexpensive relative to servo
> motors of similar power. In my application I'm more tolerant of
> backlash than expense.
>
> Thanks in advance.
>

DC motors are not in them selves expensive but DC servo motors are
because they have the relevant properties required for good servoing.
If you want a cheap DC servo motor you could try a normal DC motor
and settle with the performance.

You can't use a single phase AC motor and any thoughts of converting
one to the other are going to cost you in time and money and probably
won't work anyway.

Why not use stepper motors? You can get them really cheap these days
and they perform really well, certainly better than a homemade servo
motor.

What is your budget by the way? I'm assuming you were going to have
to buy servo drives so it can't be that small.

Graham