[TowerTalk] Motorized Crank Up Towers

knormoyle at surfnetusa.com knormoyle at surfnetusa.com
Thu May 20 12:33:49 PDT 2010


maybe someone can answer this for me.
I've been thinking, that based on everything said, that cable corrosion is the main issue to worry about.

Steve's example of motor-driven failures got me wondering about the max force a typical motor setup can put on a cable.
Obviously there's gearing.

The system has to be designed minimally for the tower weight, friction, and an unknown amount of antenna/mast/rotator/cable 
load. I suppose there's static friction to overcome from a stationary position also, so that's more.

I'm wondering how much force the motor can put on the cable without stalling. Is it 2-3x the maximum force needed?

If so, does that mean the cable broke at 2-3x working load?

Or did the motor put 10x the working load on the cable without stalling? 

I'm wondering if the real issue was cable weakness, even if it was the motor pulling on it. I would think the numbers work 
out so that the cable should be able to tolerate the max force from the winch possible (even if tower is stalled). (assuming 
a new cable, not degraded by corrosion?)

Don't know though. Thoughts?

-kevin
ad6z

 



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