[Towertalk] Prop pitch motor problems

W0YG Charlie Summers w0yg@plusten.net
Mon, 5 Aug 2002 21:10:52 -0000


Greetings to the list.

Maybe two years ago I installed a small prop pitch motor under an 80 meter
yagi with 62 foot boom.  This yagi had chewed up three rotors previously
which will remain un-named.  I thought my problems were cured with the prop
pitch.  Well, not so.

Within the first year, the yagi started turning counterclockwise in the
wind.  I would park it due north but overnight it would creep in a wind over
to say 330.  OK, I would go re-orient the yagi and within a couple of weeks
it would creep over to say 300.  All the while the rotor controller in the
shack would tell me it is still due north.  So, I thought I better pin the
antenna to the mast.  I did this but the creep continued.  So, I pinned the
mast to the prop pitch rotor.  The creep continued.  Somewhere in that prop
pitch motor something is slipping but only counter clockwise.

I changed the prop pitch  motor over to a spare that I had.  The problem is
cured.  No counter clockwise creep.

I disassembled the prop pitch and find that somewhere along the line a bit
of water go into the gear section but not bad.  No bearings were rusted but
a sleeve was rusted pretty bad.  I have removed the "gear sandwich" and all
gears down to what I refer to as the bicycle gear just above the motor and
don't see anything wrong.  I cannot turn any gears by hand which is how it
should be.  When I turn the motor shaft, all the gears turn.

Somewhere something is slipping but only in a westerly or counterclockwise
direction.  Can someone give me some guidance on this problem.  Rather
perplexing.  What could it be?

73,

Charlie, W0YG..>>