[TowerTalk] Prop Pitch Motors

[CubexCo at aol.com]

In a message dated 7/13/2004 10:00:23 AM Eastern Standard Time, 
towertalk-request at contesting.com writes:
John now has nearly a dozen prop-pitch motor/selsyn cables laying on the
ground without any indication (so to speak) of what the connections are at
the tower.  It would be really great if someone could suggest a method -
such as an ohmmeter or DC measurement - that would allow him to figure out
the connections without having to laboriously climb up and down the towers a
million times.

I've volunteered to help figure this out for John, but maybe this would be
of help to others with "mystery wiring", too.  Such nfo might be of use for
troubleshooting.  Suggestions?

73, Ward N0AX
=====================
Ward,
Sounds like a great treasure with "dozens" of prop pitch motors.  They are my 
favorite rotator, tough and reliable.  Checking out the windings from the 
ground may be difficult with out having some idea of the circuit used.  The 
motors are simple, a common pole, and CCW and CW pole.  Look for the common 
polarity indicators such as RED, WHT or BLK leads, also the heaviest conductors will 
likely be the motor feeds.  
Also there is likely to be limit switch circuitry which will have its own 
common, or be connected to the motor common and then two leads for CCW and CW 
limit signal.  That is a minimum of 5 wires. 
Using the heaviest wires and with a 28volt power source it is a touch and try 
proceedure - note the polarity and direction of rotation. 

If the Selsyn transmitter wires are included that is another minimum of 4 
wires if one of the S windings have been connected to one of the R windings.  
Sorting out which is which remotely may not be possible.  But one climb and 
inspection will likely set the pattern which could be used for all other indicators.

Regards,
Norman W4QN

http://www.cubex.com/