[TowerTalk] Why did my Tailtwister stop turning?

[Paul Playford]

My experience indicates you have a sticking brake wedge.  

My Ham M had a V shaped wedge and the brake never stuck.  Several years ago
I rebuilt the rotator and for some reason replaced the wedge with the
current product, which has a square face.  And the wedge would sometimes
stick.  I went back to the old V shape and no more problems with that rotor
(still in use after 40 years).

My T2X would quit turning.  I brought the rotor into the shop and everything
was fine.  After several up and downs I noticed the brake was not sticking
anymore and thought I had finally fixed it.  The next time I had antenna
work to do and went to remove the rotator I observed that the mast, antennas
and rotator were supported by the thrust bearing - the rotator mounting
plate was a good 2" above it's resting point in the tower (the LM-470 plate
floates in the tower).  When I reinstalled the rotator I made sure it was
carrying the weight of the mast and antennas and the sticking brake
returned.  So it's back to everything hanging on the thrust bearing now.

Every once in awhile the brake does stick again but I have found that by
running my tower down a bit and then back up the brake releases and I'm back
in business.

Next time I re-lub the rotator I will grind down the brake wedge a bit to
give it more clearance.  I assume the clearance between the brake wedge
surfaces and the teeth in the housing is very close to prevent antenna
movement in the wind and the subsequent grinding of housing teeth but I will
take that chance.

The Ham M has turned many different antennas - the heaviest load was a
204BA, 153BA and 103BA stack.  The T2X turns long boom 4 element monobanders
on 20, 15 & 10.

FWIW, the capacator in the control box will age and require replacement.
The symptoms of a defective capacitor is the rotor just slows way down when
turning, eventually the rotator will not turn at all.  I find that MFJ is
very reasonable on priceing for replacement parts.

de Paul, W8AEF
 

-----Original Message-----
From: towertalk-bounces at contesting.com
[mailto:towertalk-bounces at contesting.com] On Behalf Of Barry 
Sent: Monday, November 29, 2004 1:35 PM
To: towertalk at contesting.com
Subject: [TowerTalk] Why did my Tailtwister stop turning?

Had a problem over the weekend with my T2X.  It wouldn't turn.  It was
working fine, then all of a sudden it was stuck at about 300 degrees.  I
tried the usual rocking back and forth to free the sticky brake, but no
luck.  All the indicator lights were normal.  I tried several times over the
next 30-45 minutes and it just wouldn't move.  
I gave up the contest in disgust, and the next day checked the rotor and it
worked fine, as if there was no problem earlier.

The rotor was refurbished about a year ago and looked brand new inside and
out.  

I don't think it was a thermal cut-out as I was not turning it a lot. 
Would an aging motor starting capacitor act intermittently like this? 
 The control box is about 14 years old.  Any other ideas?
Tnx,
Barry W2UP--
Barry Kutner, W2UP              Internet: w2up at mindspring.com
Newtown, PA                     Frankford Radio Club

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