[TowerTalk] Motorized Winch for US Tower

[K8RI]

On 1/2/2013 10:50 PM, Richard (Rick) Karlquist wrote:
>
>
> On 1/1/2013 7:19 PM, Eugene Jensen wrote:
>> I personal have no working knowledge of the W3000 worm gear but my only
>> concern is it design be driven by a drill motor. I use a Thern worm gear
>> 4WM2 motor driven and it is designed for this kind of service. I many
>> years
>> ago on a small Hygain Tower blew the gears set driving it with a drill. I
>> was lucky that it happen at the start. I use mine on the tilt over on a
>> HDX555.  I have used a Hole Hog to drive it. It has two speeds and yes
>> you
>
> Good point.  The W3000 gets hot if you crank it too fast.  The Hole Hawg
> has a fixed 500 RPM speed.  The next model down right angle drill has
> variable speed.  You need to take it easy with the drill.  Keep it
> down to 100 or 200 RPM.  My W3000 has started to make squeeking noises.
>   I have been looking for something with a higher rating but most other
> winches are only 2000 lbs.  I might go with something like what is shown
> here:

I think the point to remember is that drill motors are not designed for 
continuous duty, not even the heavy duty ones. I burned up a brand new, 
heavy duty Dewalt hammer drill, drilling 3/4" holes in a guy anchor 
brace in under 5 minutes.

If you look at the motor driven winches, they use a monstrous step down 
through spur gears which puts very little load on the motor just as in 
the ham series of rotators.  The motor itself has so little torque you 
can stall it with the pressure from one finger. Drill motors OTOH 
provide considerable torque, but generally for a short period as the 
motor is small and is not very efficient at getting rid of heat. The 
larger rotators using a double worm gear have a  motor capable of 
substantial torque although the double worm gear multiplies the torque 
substantially.

Variable speed Drill motors develop substantial heat when operated at 
low speeds/RPM under load. they can not get rid of the heat efficiently 
at low RPM and cooling is critical for these small motors.  Two speed 
drills use gears and run the motor at full speed so they have better 
cooling.

This is often a problem with inexpensive winches when used to raise 
towers.  If it takes 3 minutes to raise the tower make sure the motor 
and winch are rated for the load and run time.

A fellow ham who lives a little over a mile from me had one of these 
winches fail last fall, with the tower about 2/3rds of the way up or 
around 60 degrees.  Got pretty busy there for a while.

A 1/4 to 1/3rd horse, 1700 rpm AC motor should likely be sufficient when 
geared down to tower raising speeds be it tilt up or extension speeds. 
I'd run the calcs before actually trying it though.

Small to medium size motors designed for continuous duty, or at least 
long run times when operated within their load limits stand up quite well.


BTW RPM should not have an "S" as in RPMS although it's often mistakenly 
written that way.  RPM stands for revolutions per minute. Put an S on 
that and it doesn't make sense as it'd be revolutions per minutes which 
is acceleration.

73  Roger (K8RI)