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[TowerTalk] Selsyn Wiring

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Subject: [TowerTalk] Selsyn Wiring
From: donovanf@sgate.com (Frank Donovan)
Date: Sat, 5 Apr 1997 20:06:54 -0500 (EST)
Hi Bernie!

Congrats on your prop-pitch!  There aren't many of these outside the USA!
Here's the info you requested on selsyn wiring:

The X and Y leads are the "stator" leads.  Simply connect 120 Volts AC
across X and Y (I'm assuming these are 120 volt 60 HZ selsyns), then run
leads up your tower to connect X-to-X  and Y-to-Y.  On some selsyns these
are labelled S1 and S2 instead of X and Y

Then connect rotor leads 1-to-1,  2-to-2, and 3-to-3.  On some selsyns
these are labelled R1, R2 and R3.

A few tricks:

If your don't wish to use five wires, three wires work just as well (all
of mine are three wire installations).  Simply ground X and 1 on both
selsyns, then run wires from Y-to-Y, 2-to-2 and 3-to-3 (this assumes you
have a good common ground between ur tower and ham shack).  Connect 120
VAC from ground to Y.  For safety, I use a small isolation transformer
between the 120 VAC mains and the selsyn so that I'm not grounding the
neutral of the AC mains!

Sometimes its more convenient to have the two selsyns turn in opposite
directions (all of mine do!).  This allows the selsyn on the tower to be
mounted upside down.  You can accomplish this by swapping any two of the
numbered leads:  1-to-1  2-to-3  3-to-2.

Your outdoor selsyn must be protected from rain!  I place mine in a
waterprood box.

Good luck!
73
Frank
W3LPL
donovanf@sgate.com


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