[TowerTalk] FW: Difference in TailTwister and Ham 4

[Roger (K8RI) on TT]

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 at telus.net> wrote:
>
>> Date: Tue, 21 Oct 2014 14:10:38 -0400
>> From: K7LXC--- via TowerTalk <towertalk at contesting.com>
>> To: towertalk at contesting.com, maflukey at 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)