>From your diagram it looks like a 2 phase induction motor. To slow
this down directly you will need to decrease the input frequency (and
possibly the voltage).
Can you drive it in a pulsed mode ? i.e. turn it on for a 100mS then
off for 100mS to cut the speed by ~ 1/2.

If you do try doing it this way keep an eye on the temperature of the
FET or whatever is used using as a control switch. If it uses a fixed
switch or relay you may need to replace then with a semiconductor
switch of some sort.

Or Change the gearbox.

Does the system have a brake on it? If so then you may also need to
make arrangements to hold this off while sending pulses.

Richard P

On 15/07/05, Mike Hord <mike.hord@gmail.com> wrote:
> > The motor speed gives me one turn of the antenna each two minutes.
> > What I need is one turn in 5 minutes.
> > This will give me more precision pointing the antenna, the reduction =
of
> > the velocity never can be variable, it must be fixed.
> >
> > The rotor is a CDE Ham IV, and has some gears to reduce the motor=B4s
> > velocity.
>=20
> You'd do best to change the gearing, then.
>=20
> What country do you live in?  In the USA, McMaster-Carr
> (www.mcmaster.com) is a pretty good source for all things
> mechanical, including the gears you'll need.
>=20
> Mike H.
>=20
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