[TowerTalk] Motorized Crank up

[Roger (K8RI) on TT]

The winches used to raise and lower "most" crank up towers used by hams 
are very simple arrangements.  They use a "relatively small", 
bi-directional 110 VAC motor to drive the take up reel through a series 
of belts and pulleys as a speed reducer. I'd need to go look to see what 
HP my LM470 uses, but it's less than 1 HP

The simplest uses 2 metal plates. One to mount the motor at 90 degrees 
to the plate with the belt and pulley speed reduction unit.   Far, far, 
cheaper than a winch or worm gear reduction unit.

Most, standard AC motors run at 1700 RPM.  A common cable take up drum 
may be on the order of 4" in diameter.  The Circumference = Pi d or 3.14 
* 4 or 12.5 inches ~ 1 foot per revolution.   You need to know how much 
1 ft of cable raises the tower.  I don't remember off hand how much that is.

Speed reduction with belts and pulleys is diameter of the larger pulley 
divided by the diameter of the smaller.

I'll leave the rest to someone who is more familiar with crank ups.

73

Roger (K8RI)

On 10/27/2015 10:40 AM, malco at carolina.rr.com wrote:
> I have a US Tower TX-455 Crank up. I think that one of these days I will
> have a heart attack cranking that puppy up. US Tower gets almost 2K for the
> motorized setup. Are there any cheaper alternatives out there?
> Tnx 73 Mal WA2TWA
>
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-- 

73

Roger (K8RI)


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