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[TowerTalk] Ham IV problem

To: <towertalk@contesting.com>
Subject: [TowerTalk] Ham IV problem
From: w7ni@teleport.com (Stan Griffiths)
Date: Thu, 30 Oct 1997 21:07:32 -0800 (PST)
Hi Chris,

Let me guess:  he did not fully test it on the ground before installing it.
I ALWAYS fully connect any rotator I have had apart to its control box and
make sure it runs end to end without trouble before reinstalling it.  Maybe
I'm wrong and he did test it . . .

Anyway, there are a few things you can do wrong when putting a rotator of
that series back together that will cause the indicator to act strange.  As
you probably know, the indicator pot inside the rotator is engaged by a
notch in the casting of the bell housing.  You have to pre-align the pot to
make sure it will engage correctly when the bell housing is installed.  What
I always do is install the part that trips the limit switches to as close to
the middle of its travel that I can.  I then set the indicator pot as close
to its center of travel that I can.  I then carefully inspect the inside top
of the bell housing to see how the housing will engage the pot.  This tells
me the exact orientation the bell housing must take when correctly
assembled.  If the orientation is off by one bolt position, the indicator
will not work correctly.  I don't think it will work quite like the
description I read either, but I can't think of any other suggestions.
Incorrect assembly would not have the indicator finding the correct
direction after a delay as described above.  I don't have a guess as to why
that happens.  Sounds goofy to me.

I would (oh, no!) take it down, take it apart, make sure it is assembled
right, and GROUND TEST IT.

Good luck and let me know if any of this helps your friend . . .

Stan  w7ni@teleport.com


>I'm forwarding this message from ZS6AWK, who is not a Reflector 
>subscriber.  I will handle all correspondence, and make sure that 
>both he and the Reflector hear about the final conclusion.
>
>It's a problem that I've seen in a number of Tailtwisters, but for 
>the past few years I've not been high enough in Maslow's pyramid to 
>worry about it!
>
>Chris R. Burger
>ZS6EZ
>
>
>
>>From ZS6AWK:
>
>I opened my rotator to give it a service after it has been on 
>the tower for quite a few years. After putting it back together
>again it would not operate properly again. When I operate the
>rotator in a CW or CCW direction it does move in that direction 
>but the meter needle starts to wander around its previous position.
>Not much but enough to irritate you. When you release the CW or CCW 
>switch it does actually settles on the new position. But one cannot 
>actually check with the meter the movement of the antenna. Only 
>afterwards, to my big frustration :-(
>
>I checked and recheck the wiring from the manual. Cannot see anything
>wrong. The only thing that I am not 100% sure of is the quality of
>the cap. But hy can the rotor part influence the meter part ? I 
>thought the metering circuit is totally separate from the induction
>motor part ? There is also a reduction in the motor voltage when I 
>operate it. It goes from 30 to 25VAC. But I had the same cable as
>before.
>As I understand it the reduced voltage will make the rotor weaker
>but why is it influencing the volt meter ? The dirction pot is also
>clean. I checked it by moving the pot rotor by hand. The meter
>moves smoothly then.
>
>
>Did anybody experience similar problems ? From some
>electro-mechanical
>expert ?  :-)
>
>+++++++++++++++++++++++++++++++++++++++++++++++
>Danie Brynard        
>PO Box 15133,Lyttelton,0140,South Africa
>GRID LOC: KG44CE,       Tel/Fax: (2712) 6640330
>+++++++++++++++++++++++++++++++++++++++++++++++


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