[TowerTalk] Telrex rotator

[Martin Sole]

Hi,

Just wanted to thank everyone for the great replies I received both on 
and off list. Some good ideas and generous offers. It really s quite a 
big beast but the overall simplicity would suggest it should be fairly 
reliable in service. If I can solve the indicator problem then about the 
only other concern I would have is the 50Hz AC feeding the motor 65 feet 
up in the air and what sort of hash this might create in use. I guess 
I'll need to probe the motor with a receiver whilst it's still on the 
ground to be sure on that.

My plan is to turn a Cushcraft X9 with it ,which seems well within its 
capabilities.

The other question would then concern the necessarily long mast from the 
rotator up through the tower and top bearing to the antenna. The antenna 
would be mounted right above the top bearing but what concerns should I 
have, if any, about the mast extending down inside the tower to where 
the rotator would live? This would be some 30 feet below the top bearing.


Martin, HS0ZED














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

>> 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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