[amsat-bb] Re: G-5500 problem

[Paul Baldock]

I think I have confirmed that the problem is the 
motor capacitor. I have connected a 47uF Bi-Polar 
Cap across the motor connections in the shack, 
which is effectively across the 100uF up at the 
motor (unless a limit switch opens), and all 
seems to be working in both directions now.

- Paul




At 03:30 PM 12/10/2009, you wrote:
>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.
>
>Regards
>
>- 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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>
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