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Winch Motors


Petergg

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My winch motor is two and one quarter litres of fire breathing fury. Will pull all day and never overheat.

Bill.

Bill, dont give away the secret of the Dibnahwinch. It is impossible to solve the problem with such a simple solution; the solution has to cost at least thousands of pounds to be any good. Electric has to be the way!

daan

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Actually a few years ago I converted an electric worm driven winch to PTO drive with the thought that I would only use the electric drive on the rare occasions that the engine wouldn't run. Trouble was the occasion was so rare that when I did eventually need electric drive the motor wouldn't run because the carbon brush holders had rotted away with condensation. The handcrank feature on my current winch is more dependable if a little slow as a backup and allows me to crank start the engine if the need arises.

Bill.

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Hi Peter,

Bow '2' are a very rare beast, i believe that less than 10 24v versions where actually sold (Don't take my word for it) because of there huge cost.

The only units i am aware of in existance, the owners will not sell, sorry i can not help you more.

Jim :)

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Why not keep your 12v motors - and over-volt them! Run on 24v and so long as you are careful, they will be fine!

Although it seems counter-intuitive, within certain bounds, they will run cooler than 24v motors.

For a given pull, the motors have to do a certain amount of work. The amount of heat generated by the motor is given by I^2R. The resistance R of a 12v motor is half that of a 24v.

Twice the current will flow, but the motor will run 4 times as fast for a given load - so to compete the job, you are generating 4 x 1/2 the heat (because the resistance is halved) = 2 x the heat, but for 1/4 the duration. That means the amount of heat you will need to dissipate is 1/2 that of the 12v motor.

The down side is that you have significantly more power available - which you are liable to want to use.

A 24v motor will give you the same advantage in heat generated, but they are wound to be the same power output. The upshot of this is that with a 24v motor, it will go twice as long at full load before overheating.

For my money, over-volting wins, so long as you keep an eye on the motor temperature. Generally they die when the armature (spinning bit) gets up to 180 deg C or so. Because the heat transfer to the case is poor, this will probably give a case temperature of about 90 deg. If you were to use a digi thermometer with the probe stuck to the case and stop winching if the thing reads over 70 say - I think it would give you the best of all worlds! You can buy over temperature alarms as well which start beeping above or below a set temp. That might be more useful!

Si

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Peter

what are you planning to use them for?

To winch up big hill's and through deep mud and water, same as you really :lol:

Si, thanks I might just do that yet, would I need 2 albrights or just run them both off 1?

Jim, I can dream about finding a pair of Bow 2's like I can about fitting your top housing :) .

Regards

Peter

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Is it possible to up the voltage as needed so you can have from 12v to 24v on tap?

Peter

You would need a PWM speed controller for that - but a monster one! A 300A, 24v controller from www.4qd.co.uk will cost almost £300.

Not a great deal of point though IMHO.

Si

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Or do you mean a switchable supply, whereby you have 12v for normal winch duties and then switch over to 24v supply for when you do a winch comp?

That would be easy to achieve. You could have a 12v circuit for vehicle and normal winching and then a separate 24v circuit for comps fed by it's own alternator.

Cheers

Steve

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Or do you mean a switchable supply, whereby you have 12v for normal winch duties and then switch over to 24v supply for when you do a winch comp?

That would be easy to achieve. You could have a 12v circuit for vehicle and normal winching and then a separate 24v circuit for comps fed by it's own alternator.

Cheers

Steve

I am about to fit a seperate 24v system on my 90 just for the winch's, I was thinking along the lines of a Rheostat, so could adjust the voltage to the motors. I use my winches a lot at Bures but do not want to run 24v through 12v motors when not needed.

Regards

Peter

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Or do you mean a switchable supply, whereby you have 12v for normal winch duties and then switch over to 24v supply for when you do a winch comp?

That would be easy to achieve. You could have a 12v circuit for vehicle and normal winching and then a separate 24v circuit for comps fed by it's own alternator.

Cheers

Steve

Something I've been thinking about is a setup that gives you 12V if you push so far and then 24V if you push further. Its a bit more complicated to get to work so I'm going to wait and see how it goes with standard solinoids before trying anything else.

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A Rheostat is essentially a variable resistor which works by dissipating energy as heat, that would normally go into the appliance.

With a winch motor, say to drop 24v to 12v. The motor could easily draw 400A at 12v, giving it an internal resistance of 12/400 = 3x10-2 Ohms.

The heat generated in the rheostat dropping half the voltage will be I^2R = 400 x 400 x 3x10-2 = 4.8kw

Assuming you could find a rheostat with that kind of rating - you would need some cooling system for it!

I suppose you could put it in the cab as a heater?

The reason a PWM speed controller does not get this hot is that in this situation it would only switch the motor on 50% of the time and off the rest. It's resistance while on is very low - so the heat generated is also low. When off, the heat generation is almost zero.

Using a PWM controller has an added advantage that although the speed is halved, the torque stays almost as high as running full 24v. The controllers generally switch so fast that you cannot see the motor speed up & slow down. You can sometimes hear the controller whine though as the switching frequency is often in the audio range.

Will's idea of having one switch position for 12v and another for 24 has more merit. The big issue with that is if you have two batteries in series and discharge one of them more than the other (the one used for 12v will be used to supply half the 24v. thus it will be used more often than the one which is only used for 24v).

It is only being charged through the other battery, which when fully charged will limit the charge rate of the 12v battery - so performance on 12v will be severely affected.

There are ways around this, like using two isolated 12v alternators, one to charge each battery - but you have to consider these type of things before embarking on a money wasting expedition.

Si

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Will's idea of having one switch position for 12v and another for 24 has more merit. The big issue with that is if you have two batteries in series and discharge one of them more than the other (the one used for 12v will be used to supply half the 24v. thus it will be used more often than the one which is only used for 24v).

It is only being charged through the other battery, which when fully charged will limit the charge rate of the 12v battery - so performance on 12v will be severely affected.

There are ways around this, like using two isolated 12v alternators, one to charge each battery - but you have to consider these type of things before embarking on a money wasting expedition.

Si

Si, I'd thought about the battery issue and my way around this would be to ake the 12V supply from the 12v setup that'll run lights etc on the truck. My theory being that I'd only use the 12v supply for technical stuff when you want to slow things down a bit so current draw won't be that high. I'm going to wait and see what real world performance is like first, though, as there's no need to make it more complicated if it isn't needed.

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Now thinking of 36v into 24v motors any thoughts?

Even better efficiency wise. Less likely to fry the motor.

Even harder to find a 36v alternator though.

You could use one isolated 24v in series with your regular 12v alternator I guess.

If you went to 48 to 96v you get in to the territory of decent traction motors which make twin motor top housings and over volted 6Hp motors look a bit gay!

(Will, Have you considered that? The motors, not the looking a bit Gay! ;) )

Si

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Peter,

Thought you knew a certain Chap that already runs a 36v system on a Hi-lux.........?

Or am i mistaken...... :)

Like the idea of 36 through 24, that is very level thinking........

Si, 36 volt altternaters are becoming available as they starting to use 36v on these new kneeling buses etc...

But God knows how much they cost...

Jim :)

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