DIYbanter - View Single Post - Help please w/ electromagnetic slip clutch

Steve W.[_4_]

wrote:
On Thu, 11 Feb 2016 22:49:33 -0600, Jon Elson
wrote:

wrote:

Can you explain a
little about how the resistor in series with the main servo and the
handwheel servo, which supplies the drag, connected in parallel with
the resistor, would work?
Well, a very small resistance would be put in series with the main motor.
This resistor would be of much lower value than the DC resistance of the
handwheel motor. The handwheel motor would then be put across the resistor.
Some portion of the main motor current would flow through the handwheel
motor, producing a torque. Possibly, you'd also place an adjustable
resistor in series with the handwheel motor to set the level of torque feel.

I really don't know if this will work, as when turning the handwheel fast
that motor will generate a voltage that will be dumped in the resistor.
But, since the servo system with the encoders will make the main motor synch
to the handwheel, these back EMF's should be able to be equalized.

This would be a cheat that would allow you to do this without a bunch of
electronics, like an extra, small servo amp. As I say, I'm not sure it
would work.

Jon
Greetings Jon,
If it works it is not a cheat. The handwheel motor would need to be
wired backward with respect to the rotation of the main servo so that
it will oppose rotaton of the handwheel. I will investigate your idea.
Simple and easy to implement. If it works.
Cheers,
Eric

How about using DC to brake an AC servo? Higher the voltage the more
resistance to motion.

--
Steve W.