Little background on a problem I'm hoping to get some "crowdsourced"
input on from Towertalkians. A few video links to show what we've
found and what I came up with to fix it once and for all....I'm very
interested in thoughts of people who have these re this fix.
Apologize for the length.
So for the last 13 years we've had 1032 Tic ring rotors in Downeast
Maine on a pair of 100' monopoles. They've turned anything from 2l
40's to 20m5's to 13 element 6m yagis. All have had issues with
jumping teeth at one time or another. Very disappointed with them.
We've always had problems with these jumping, having to adjust
motors, 5 different kinds of motors, and the size stunk to climb
around. Last year we were forced to demolish the poles and
reconstruct because of a serious corrosion/construction issue. As
part of this re-install we bought all new 1022 Tic rotors because I
was told alot of the issues we had were fixed on this newer model.
Well it turns out that it wasn't and it's left us with spending a
crap ton of money and not being able to use the new LFA9 Innova 6m
antennas we put up in November. With 6m TE propagation season
approaching this has got to get fixed and what follows in the last
video link below is what I came up with in my fabrication shop.
Since last fall we have been fighting with these things to make them
work, we've been dealing with warped & out of round rings,
bent/sloppy welded motor mounts, improper length positioner brackets,
all kinds of stuff that just shouldn't be. Because of the
motors/rings jumping teeth on their own, we ended up having to put 4
pairs of vise grips on them for the winter to lock them down so we
didn't lose our custom 6m phasing cables. They rotated by themselves
sometime in the first 3 weeks they were up. No good. Since the site
is empty there isn't anyone there to watch them constantly, they had
to be fixed for the nasty Maine winter.
Long story short, it ends up the problem is all because the ring is
floating inside the bearings and if you adjust the triangle cage too
small the ring binds because it's not perfectly round (triangle C
frame support becomes a non-equilateral triangle and jams the
elliptical ring on 2 sides). So the adjustment has to be done on the
C frame slide bolts to allow the rings to move freely. This causes
the rings to move or "torque" from side to side depending on which
way they are being commanded to turn because the ring moves inside
the bearings too much, and since the motor is mounted solid and the
ring is floating, it becomes impossible to adjust the motors to stay
enmeshed 100% of the time.
Several weeks ago we went up and took the vise grips off one unit,
and this day coincidentally had 35-40 knot honkin winds. We were able
to troubleshoot why it was jumping teeth on the gears. It all had to
do with design and how the ring "floated" inside the triangle
bearings. This is the first time I've really been able to see the
issue because of the winds and we got nice video of it. Normally the
antenna weight and size is prohibitive to trying to troubleshoot this
and we've never actually seen these rings jump teeth, we were
thinking the motors were backturning.
Here's a couple of videos that show the ring movement and the teeth
skipping. These are private/unlisted videos pse don't pass these links around.
This first video is when we first got there. You can see the ring
move and become unmeshed from the motor almost right away. The second
video is after we ran it around a few times and you can hear and see
the ring teeth slipping.
https://www.youtube.com/watch?v=6McNoalB36g
https://www.youtube.com/watch?v=oj1Gu1daRi4
So fast forward to today where I assembled a complete ring in my
shop. I originally had a plan to cut the motor bracket off and weld a
heavy duty strap hinge to the back of the motor and use that as a
pivot mount to the triangle C frame, then fabricate a custom bracket
with a heavy duty tension spring to "pull" the motor into the gear so
it could never jump teeth. As some of you may know they changed from
the original single motor/pot combination to this split
motor/positioner assembly with these new rings. This is good in that
it makes it easier to change the positioner pot module or motor, but
bad in that it makes it very difficult to mount this stuff because
they mount together using the motor bracket bolts.. The original
positioner brackets we got were 1" too short to get the gears to mesh
so we had to custom fabricate a positioner module holding bracket to
make it work last fall.
What I came up with was a cam follower bearing to captivate the motor
into the ring as shown in the video below. I discussed this idea
with Carl at Tic Gen several years ago with the 1032 rings that were
up previously. I decided to give it a shot on the test ring in the
shop and this is what I came up with. Although the ring is way out of
true, I put my full body weight into this thing today and was able to
put my b&k 36V 2.5a bench supply into full current limit and stop the
ring from turning all the while making it jump etc as you see in the
video. It doesn't jump teeth at all now...and I beat the snot out of
it. What follows is a video I shot to show to Tic Gen.
https://www.youtube.com/watch?v=1IHgADejsmM&feature=em-upload_owner
My issue with this as it says in the video is now what I've done is
fixed the motor to the ring but am concerned that a heavy windloaded
torque/long boom antenna rocking in wind could cause the motor bolts
to slide on the C channel because all the weight/torque is now
transferred to the 2 motor bolts and the ring is being "forced" into
one position on one side of the triangle.. While the possibility I
think is slim, I think it's a valid concern. I'd be very interested
in hearing what others who have had ring rotors have to say about this.
This is a 10 minute/$20 fix for an otherwise unreliable design that
makes them 100% reliable again and hopefully should eliminate having
to mess with these things again and again as we have over the years.
Tnx for reading
Scott N1CX
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|