[amsat-bb] Re: Motor for Yaesu G5500 Azimuth Rotator?

[WA6FWF]

Hi David,
     As you found out shaded pole motors do not pull more current when 
they stall, they
actually pull less and so they wont blow the fuse, they just sit and cook.
     So while your changing the motor now might be a good time to put 2 
thermal cutout switches
inside on the windings so this doesn't happen again,it takes two, one 
for each direction.

http://www.devale.com/battery-protection/miniature-bimetal-snap-disc.html
or
http://www.pepiusa.com/prod.html

explains them, and you can find them in small quantities at

http://www.allelectronics.com/make-a-store/category/765/Thermal-Fuses-Breakers-Switches/1.html

or at other places...

73
Kevin WA6FWF



On 2/23/2012 6:31 AM, David Palmer KB5WIA wrote:
> Hi Everyone,
>
> Well I'll be QRT from the sats for a little while!!  After replacing
> my UHF antenna on the backyard satellite array, I managed to catch the
> (slightly longer) new antenna on the house roof and jammed the Yaesu
> G-5500 rotator, ugh!   Even though I had replaced the normal 2-amp
> fuses in the controller with 1-amp fuses, the azimuth motor still
> managed to overheat and burn out.
>
> I disassembled the azimuth rotator, and although the gears, bearings,
> switches, and capacitor are all OK, the motor has quite a burnt smell.
>   Bench-testing the unit with motor removed from the assembly shows the
> motor doesn't spin at all in one direction, and spins slowly but draws
> high current in the other.  Coil windings are in series for
> left/right, should be 3.5 + 3.5 = 7.0 ohms, and the right coil is
> showing only 1.0 ohms resistance.  The azimuth motor is definitely
> toast.    Fortunately, the controller is OK (both the Az and El sides
> of the controller successfully control the elevation rotator).
>
> I just got off the phone with Yaesu parts, and unfortunately the
> replacement motor has been backordered from Japan since December.  No
> estimate yet of when more might come in.
>
> Question to the list:  does anyone have a G5500 azimuth rotator with a
> working motor available for parts?  Or any other ideas for
> replacement?
>
> 73!  Dave KB5WIA
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