Winch Experts wanted

In article 405fd00e$1@darkstar, says...
I'm also getting the impression that one can use a much less
powerful electric motor becase the amount of HP getting to the
cable and ending up as effective pull is much higher than
for a traditional fuel motor. I'd like to really know what
a 100 hp electric would do in terms of accelerating a
500 pound glider.

100HP is getting up there. I'm sure it would accelerate a 500lb
glider quite nicely. This is out of my area of expertise, but can
easily be done by somebody with the knowledge of tractive systems.

Thinking more about advantages and disadvantages, electric
shock could be a biggie,

Actually the threat of electrical shock is minimal compared to that
of the mechanical hazards present with rotating machinery.

and I imagine there IS some heat generated.

Heat is not an issue. The efficiencies of modern electric motors will
approach 95%, whereas the efficiency of an internal combustion engine
is on the order of 20-25%.

Wear is likely less of an issue, perhaps
brush changes once in a while. Designing it with spectra
in mind seems a good idea...reduces the weight of line and
thereby the HP requirement. This shifts the expense from the
initial expense instead to ongoing expense (replacing and repairing
expensive rope). I'd favor this. Anything that allows the
same UMPF for less initial investment...

I can't see the first cost of an electrically driven winch being
competitive with an engine driven winch. Where I see the economic
advantages are in the life cycle costs of the winch. An electric
motor, with its one moving part, is very reliable.

Having such good control of the motor seems like it would really
improve efficiency too. Sure sure, expert winch drivers
do great things, but it would be nice to not need "experts"
to do something that should be simple...

This is where I see one of the advantages of electric drive with a
programmable variable speed drive. I take a look at modern chair
lifts found at ski resorts. Multi-speed, multi-stage and operated by
people that, well, lets not go there.

Anyway, I was just kinda thinking out loud, in a written sort of way.


One other possible inefficiency...I wonder how much electric
attenuation occurs over even thick power supply cables.
But I definitely think electric winch is the way to go...

Bill Daniels wrote:

that can be pulled by a mid-size pickup or SUV (under 4000 lbs. total).
Anything larger, or built on a truck is, in my opinion, not
practical
for anything other than primarily fixed site usage.

I've seen a bunch of surplus 150 to 200 hp electric motors
for $3,000 to $5,000. Seems like a very logical choice (much cleaner,
easier to control, not as much fire danger, simple, etc.).
But definitely this is a fixed winch (and how does one get 500 volts and
100 amps for a power supply? At Avenal if it ran
the whole city might go dim The 50 car batteries idea is only
$2,000 to $5,000 but one wonders if this and a generator isn't
Avenal, California, USA
I have seen EV Dragsters with electric forklift motors putting out 500
HP. Can pull a 3000 lb car Down the 1/4 mile in 14 or so sec.
Now where to get the 440 volts dc from

home built up to 70 mph, 50 to 100 mile range, 1000 foot lbs of torque
Lots of info here.
http://groups.yahoo.com/group/EVList/messages/

Before you guys get too far into an electric winch design, look up
"Ultracapacitors". Basically these are huge electrical capacitors that can
charge and discharge at extremely high amperages. Maxwell Technologies in
San Diego that makes the best ones in the world.
http://www.maxwell.com/index.html

Use a small generator set to charge a bank of ultracaps, then dump the
accumulated charge into your 500HP forklift motor.

Bill Daniels




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Mark Boyd
Avenal, California, USA