[amsat-bb] Re: G-5500 problem

i8cvs domenico.i8cvs at tin.it
Thu Dec 10 13:31:53 PST 2009

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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