12v vinssi 24v autoon?

[mikjus]

Briteissä winch challenge jätkät ajaa 12v bowmotoreita 24 voltilla. Mut sitä ei ehkä "tavan" motti kestää.


Tässä hieman lainausta eräästä keskustelusta forums.lr4x4.comista.

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!

lisää....

All the top Aussie teams run 24v through 12v motors.

Most expect a life expectancy of somewhere around 18months to 2 years from there motors.
Tjhe difference is they service there motors regularly, blowing out the carbon dust etc...

There winching is very voilent and extremely hard. The reason they use 24 through 12 is that it is like Nitro charging your winch, it will pull like hell and never give in and at great speed.

What actually kills the motors is over revving. This usally occurs when winching cable out of load.
The Aussies have got over this by using free spool systems, however there are people that don't.
Paul Wightman has been running 12v Xp's with 24v going through them for over a year with no troubles and they are still has fit as the day he fitted them.
The only really usefull bit of info in this thread so far is the person that wrote "Flat batteries kill motors" this is correct.

Three of our Twins have just done the Rain forest challenge unfortunately all the teams had to be rescued and 50 cars left in jungle due to severe monsons and flooding, but those using 24 through 12 suffered no problems and were amazed at what they where having to pull through just to stay out of danger.

So there it is, Yes you can. But do remember to pulse the out button if you are paying out. If you want to see how quick they are i recommend watching the Alpine challenge 2007, where almost all the cars were using twin motor setups (either ours or Wazzas) resulting in 5 of the top 6 places for us and ALL including the rest of the top ten using 24 through 12.
Doing stuff that most would call impossible and almost ALL will never do.

ja vielä lisää...

Over volting motors works pretty well - with one or two caveats.

Over-revving a motor can damage it. If you double the voltage, you will double the no-load speed of the motor - which may be enough to centrifuge it to bits. Don't run the motor with the free-spool engaged.

If the motor is stalled, you are putting twice the current - four times the power through the motor - so it will let the smoke out four times as fast. Don't let it stall - and be careful when it is labouring.

On the plus side, to extract you from a given hole, it takes a certain amount of energy. It is the inefficiency in the motor which makes it heat up. By running the motor twice as fast, and finishing the recovery faster, despite putting more power through the motor you actually get less heating for a given energy delivery.

This means that your battery lasts a little longer and so long as the caveats above are observed, you can winch further before the motor overheats.

Many 'grown-up' motors do not have a specified operating voltage but instead a rpm per volt rating and a max power (Lemco motors for example). The specified operating voltage for a motor is actually a bit arbitrary and is chosen to give the required rating. A winch motor is not continuously rated, but it is at a lower voltage.

The bottom line is that over-volting is fine so long as you are careful about over-doing it.


Että semmosta ja jotkut ajaa 24v moottoreita 36 voltilla mutta se onkin taas ihan oma juttunsa.