[TowerTalk] Telrex rotator

[Steve Maki]

Martin,

Many years ago I was faced with a similar situation with my medium sized 
Telrex rotator.

After much thought I came up with a solution using a mostly gutted 
HyGain Ham4 rotator (mounted under the mast drive sprocket) and a 
modified HyGain control box.

See:
https://app.box.com/s/w55jzicmz24ual5inzgkgxapo71p7f8c

for a note about it and my original Telrex manual, such as it was!

-Steve K8LX

On 11/16/18 0:04 AM, Martin Sole wrote:

> 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.