[TowerTalk] HF winch

[Roger (K8RI) on TT]

On 2/3/2014 2:43 PM, Mike Reublin NF4L wrote:
> Boy was I off on this one!
>
> Mike NF4L
>
> On Feb 3, 2014, at 9:19 AM, Mike Reublin NF4L <nf4l at comcast.net> wrote:

"I think" it's Sin( angle from winch to anchor point on tower(Weight of 
the tower X (ratio of length above the pivot to length below the 
pivot)Normally is greater than 1 X (weight above pivot/weight below 
pivot))  Assuming the cable fastens to the base of the tower rather than 
part way up to the hinge.  Then you'd have to take into account the arm 
(length above the pivot/length to cable attach point below the pivot.  )
That raises the load on the cable very fast.

The last time I did these was in 87 so I may be off a bit. No guarantees.

IE Assuming the tower is pivoted at 12 feet rather than tilted over on a 
hinged base when the tower is vertical angle = 0, Max load in this 
configuration is with the tower top is just above the ground..

73

Roger (K8RI)

>> Hi John,
>>
>> I'm not an engineer, nor have I stayed at a Holiday Inn Express lately... ;-o} but I have seen one on TV.
>>
>> The pull will at worst be at about a 45 degree angle, and using double pulleys effectively halves the load to about 600 lbs. I don't think the pull could be more than the weight, unless it were horizontal, then you'd have to account for friction or the fact that the load is pinned in place by the base bolts.
>>
>> I don't know if that would actually cut the draw to something the PS could handle, but the 55 amps is for a 1000 lb. pull. The power leads are 10 ga. stranded.
>>
>> Maybe we can get an engineer to chime in.
>>
>> Mike NF4L
>>
>>
>> On Feb 3, 2014, at 8:53 AM, john at kk9a.com wrote:
>>
>>> I am not a mechanical engineer, wouldn't the pull on the cable be
>>> significantly more than the weight of the tower when tilting it?  Then you
>>> plan on running a 55 amp motor with a 20 amp power supply?
>>>
>>> John KK9A
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