[TowerTalk] Telrex rotator

[Steve Lott]

Yes as Patrick pointed out I meant AC

not enough Coffee before getting on the computer :)

cheers!
Steve
KG5VK

http://sdxa.blogspot.com/
KG5VK Blog

http://www.KG5VK.com
My Ham Radio Friends



On Fri, Nov 16, 2018 at 6:34 AM john at kk9a.com <john at kk9a.com> wrote:

> I had one of these rotators and I never had an issue which was a big step
> up from the Hy-Gain HDR-300 that it replaced. Sadly the resale value is
> poor and I almost gave it away when I switched to using prop pitch
> rotators.
>
> If it were me, I would replace the selsyn with a potentiometer and then
> almost any control box would read the direction, especially a Green Heron
> where you could calibrate the indication. The remaining issue would be
> supplying 120v to the motor. This could be done with relays activated by
> the low voltage control box or perhaps W2FU has a better solution.
>
> John KK9A
>
>
>
> From:   Martin Sole hs0zed
> Date:   Fri, 16 Nov 2018 12:04:18 +0700
>
>
> Hi,
>
> I'm restoring a Telrex A3695RISX rotator. It's quite a monster but if I
> can figure out a way to use it I think it's unlikely I would ever need
> anything bigger, 1/3hp reversible AC motor, dual worm reduction gearbox,
> chain drive to 3" output shaft and it weighs about 125 lbs, around 57kg.
>
> I have no control box which poses a small problem. Wiring to the motor is
> straightforward enough though I think the limit switch arrangement could
> be handled better.
>
> It uses a selsyn for position indicating. In this case actually a General
> Electric Selsyn Control Transformer 2J161. This is marked 57.5-57.5 V
> 400CY. The device is working in that I can get the three outputs from the
> stator winding when I excite the rotor winding, all three stator outputs
> rise and fall with rotation so I'm pretty sure its good.
>
> The problem is what to do at the other end. Without a matching selsyn, not
> something I expect to ever turn up around here, I am wondering how I might
> be able to take the selsyn outputs and interpret them by some other means.
> My understanding is the 3 stator outputs are AC voltages varying in
> amplitude and with a fixed phase relationship in order to produce an
> unambiguous value related to absolute position. I'm not 100% on this yet
> though. They are in a delta configuration though so I'm thinking anything
> I do first needs to make them Y configured
>
> What are my options?
>
> I had thought about an I2C compass module but that will entail placing
> some other conversion hardware at the rotator to convert to something like
> RS422. Any other thoughts. Just looking for ideas to think of what might
> work well enough. Ideally keeping the selsyn as it's all purpose built
> around that.
>
> Martin, HS0ZED
>
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