On 10/22/2014 9:40 PM, Ray Benny wrote:
They are a real struggle. You have to be quick on brake release and
applying power. When you release the brake the power has to be there.
Too quick and it binds, too slow and you don't have the power to stop it
from windmilling.
I tore up two Ham IVs and an HDR300 with the big array on windy days. I
finally gave up and put a defunct Ham IV in there with the brake set
until I could get a real rotator in there.
I should add that the HDR 300 wasn't wrecked, but had to be taken down
and realigned. Now knowing what they are like inside, "I think" I
probably could have jumpered out the limit switches and done it in
place. BUT as the pigtails to the all the antennas in the stack were
ruined, it had to come down anyway. When I released that brake, the
antennas went around so fast that it pulled the cables tight over the
top edge of the tower, stripping the jacket off and kinking 3 of the 5
over the edge. When I released the brake, the direction indicator just
snapped around to the peg before I could even let go.
At that point I decided that with that much "stuff" up there, a double
worm gear drive was the only way to go.
Unfortunately the one I chose (
http://www.rogerhalstead.com/Gears.htm) had some design flaws.
I'd not use a ham series on anything bigger than a big tribander and
there are tribanders I wouldn't use them on. We have too many windy
days. This isn't a high wind area (think it's only 70 MPH), it just
blows often in the fall, winter, and spring. Only the summer is
relatively calm except for a few violent thunderstorms,
73
Roger (K8RI)
Jim,
Good analysis. That comes out to 67 ft/lbs for the H4 and 83 ft/lbs for the
TT.
I can understand that if there is a good wind on a long boom, multi-element
antenna, both would struggle to get started.
Thanks,
Ray,
N6VR
On Wed, Oct 22, 2014 at 6:07 PM, Jim Thomson <jim.thom@telus.net> wrote:
Date: Tue, 21 Oct 2014 14:10:38 -0400
From: K7LXC--- via TowerTalk <towertalk@contesting.com>
To: towertalk@contesting.com, maflukey@gmail.com
Subject: Re: [TowerTalk] FW: Difference in TailTwister and Ham 4
torque values
My question, and I have searched, what is the difference in
starting/running torque between the Ham 4 and TailTwister?
There is no difference in torque output between the Ham IV and the Tail
Twister.
Wrong. On page 154 in my UP THE TOWER book, the comparison table of
rotators has the Ham IV with 800 inch/pounds of rotating torque while the
T2X
has 1000 inch/pounds - a slight improvement. These are manufacturer's
specs.
Both use the same drive motor and running gear ratios. The Tail
Twister has a stronger rotor housing, improved mounting fastener
arrangement, and a stronger brake wedge setup.
In some instances, they use the same parts.
Cheers,
Steve K7LXC
TOWER TECH
and
_www.championradio.com_ (http://www.championradio.com)
Cell: 206-890-4188
## To really do it right, take the inch lbs value.... and divide by
12.... to get ft lbs. Then compare
that to your typ tq wrench..and u will see that both the ham-4 and tail
twister really don’t have a lot of tq.
Start up tq is really a myth. It only last 1-3 secs... and is caused by
the high start up current in the
motor itself. I measured several of these small dc and ac motors..and
they typ have a start up current
of triple the running current.
Jim VE7RF
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73
Roger (K8RI)
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