[amsat-bb] Re: G-5500 problem

Paul Baldock pbaldock at verizon.net
Thu Dec 10 15:30:18 PST 2009

Thanks for your thoughts.

The current is about 2A when stuck or moving. (Same in both directions)

I can get it to move if I up the voltage a little 
with a series transformer. Nominal voltage is 
about 28V in the shack. By adding 10V it moves 
fine. So temporarily I will add a series voltage 
to "kick start" it, until the wx warms up and I can service the rotor.


- Paul  KW7Y

At 01:31 PM 12/10/2009, you wrote:
>Hi Paul, KW7Y
>I suppose that you measure:
>Between A6 and A4 for CCW = 4.4 ohm
>Between A6 and A5 for CW    = 4.4 ohm
>I suggest you to put an AC ammeter 5 Amps f.s. in series between the
>common terminal A6 of the control box and the wire coming up to A6
>in the motor.
>In this condition the AC current running CW or CCW must be about
>the same.
>If the current increases when the motor stuks in CW position then there
>is a mechanical problem inside the rotator.
>If the current is low when the motor stucks in CW position probably the
>capacitor C 35 losted capacity and if  the current is zero probably the
>limit switch SW-7 inside the rotator is defective.
>Unfortunately if the AC capacitor C35 = 100 uF AC wich is connected
>between A4 and A5 inside the rotator losted capacity you cannot measure
>its capacity from the shack.
>The motor is a brusheless  AC asyncronous motor using the starting
>capacitor C 35 to produce a 90° phase shift between both windings.
>73" de
>i8CVS Domenico
>----- Original Message -----
>From: "Paul Baldock" <pbaldock at verizon.net>
>To: <amsat-bb at amsat.org>
>Sent: Thursday, December 10, 2009 3:22 AM
>Subject: [amsat-bb] G-5500 problem
> > I have a G-5500 that sometimes will not turn clock wise(CW) but will
> > turn counter clockwise (CCW) OK. When it is working OK in both
> > directions each winding (CW and CCW) measures about 4.4 Ohms in the
> > shack. When it will not turn CW that winding measures about 2.2 ohms
> > (The CCW winding still measures 4.4 ohms).
> >
> > The Controller is fine, so the problem is in the motor.
> >
> > Does this motor have brushes?
> >
> > Any thoughts on what the problem might be?
> >
> > Thanks
> >
> > - Paul KW7Y
> >
> > _______________________________________________
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