Actually, that system worked very well. The same
technology was used in Diablo Hytype II printwheel and
carriage motors.
I once repaired these, and their Qume clones; The
Qumes had optical encoders that would get dirty, fail
and were very difficult to clean without breaking the
encoder glass. The Diablo's would work fine in very
dirty environments.
--- Tony Duell <ard_at_p850ug1.demon.co.uk> wrote:
> > So you want to build a contrabass? I have never
> heard one...
> > but I have always been skeptical about its ability
> to put out HiFi.
> > The reason is that people use DC servomotors with
> *brushes*, and
> > believe, the behavior of these things at low
> speeds is very nasty
> > in terms of nonlinearity: static friction,
> nonlinear torque(i,theta);
>
> It never fails to amaze me that the head positioner
> in a Diablo Model 30
> hard drive (aka DEC RK02, RK03) is a
> permanent-magnet DC motor with
> brushes. It drives the heads via a rack and pinion
> mechanism. On top of
> the motor spindle is a pair of PCBs that form a
> 'transformer' which
> provide the Sin and Cos signals for the servo (like
> the optical
> transducer in an RK05).
>
> Somehow they got this servo to work...
>
> -tony
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Received on Thu Oct 31 2002 - 08:38:01 GMT