New year, new winch mod.

[BogMonster]

The Aussies tend to do it to winch motors too. Heat build up seems to be the biggest problem running like this.

Not surprised

Try running a toaster on 415v 3 phase for a demo

[FridgeFreezer]

For no reason other than boredom I'm going to do some maths:

P = I²R

I = V/R

So if R is constant (Motor winding resistance*) when you double the voltage you double the current, so the square goes up an f-load

Plucking numbers out of the ether, assuming a 4.6HP motor is = 4.6 * 750 = 3450W of electrical consumption @ 12v which is 287.5A flat out. That gives us the resistance of the motor, R, as 0.042 (ish) Ohms. You can begin to see why clean connections, good solenoids and big cables are important as it doesn't take much poo to give more than 0.04 of an ohm's resistance

Aaaanyway, we have a motor with R = 0.042 and we stick 24V through it:

V/R = 571A

571² * .042 = 13694W = 18hp

This is all lovely in theory as it looks like you're gaining a heap of power for not much effort. But this is maths not the real world. Those motors are going to get hot, and with 24V pushing the current through they can get a lot hotter a lot quicker - the electrical input power has been squared, but if output power doesn't rise accordingly all that extra energy has to go somewhere.

Assuming a motor may be ~80% efficient, that means it needs to dump ~20% of the power input as heat. At 12V that's 690W (so about one toaster's worth ). At 24V it's 2739W :blink: you're gonna need some serious cooling on that puppy.

[white90]

Paul Wightman has cooling on his twin motor'd 8274 with temp sensors fitted

he was mentioning that the motors weren't getting hot enough to warrant the cooling last time I saw

him at FCSW3.

I'm assuming twin albrights are used on these set ups as a single contactor would be a big bugger if available

[will_warne]

For no reason other than boredom I'm going to do some maths:

P = I²R

I = V/R

So if R is constant (Motor winding resistance*) when you double the voltage you double the current, so the square goes up an f-load

Plucking numbers out of the ether, assuming a 4.6HP motor is = 4.6 * 750 = 3450W of electrical consumption @ 12v which is 287.5A flat out. That gives us the resistance of the motor, R, as 0.042 (ish) Ohms. You can begin to see why clean connections, good solenoids and big cables are important as it doesn't take much poo to give more than 0.04 of an ohm's resistance

Aaaanyway, we have a motor with R = 0.042 and we stick 24V through it:

V/R = 571A

571² * .042 = 13694W = 18hp

This is all lovely in theory as it looks like you're gaining a heap of power for not much effort. But this is maths not the real world. Those motors are going to get hot, and with 24V pushing the current through they can get a lot hotter a lot quicker - the electrical input power has been squared, but if output power doesn't rise accordingly all that extra energy has to go somewhere.

Assuming a motor may be ~80% efficient, that means it needs to dump ~20% of the power input as heat. At 12V that's 690W (so about one toaster's worth ). At 24V it's 2739W :blink: you're gonna need some serious cooling on that puppy.

You can see why some people replace the soft solder with silver solder inside the motors

Paul Wightman also runs a water jacket on his setup which also seems like a bloody good idea.

[D9OSV]

You would expect them to be red hot......

Even we expected overheating problems and fitted cooling pipes to the motors etc.....

However the reality seems to be different.

After that long hard pull you watched, we jumped out of the cab and rushed to the front of the vehicle.

To our suprise, we found both motors cool to touch including the end cap with the brushes!

Obviously they were warm, buty hardly worth noting.

We out this down to the reduced effort required by the motors due them sharing the load.

However, most will run 12volts and will not have any need to concern them sevles with these luxury problems.

We will be conducting FULL field trails with load cells and measuring equipment shortly, however until then please feel free to do the maths. I have found this thread very intresting and like the banter as well.

Kind regards

Jim

[FridgeFreezer]

Oh I forgot twin motors - that means 1142A current draw and over 5kW of heat to dissipate

I'm guessing most don't get as hot as those numbers would suggest as they rarely pull near their limits. Has anyone got specs on what battery cable they're using to power these beasties as 1000A is a helluva lot of electrons to move around.

[white90]

2.5mm twin and earth

works just fine

[FridgeFreezer]

2.5mm twin and earth

works just fine

Pah, I was expecting a nice bit of jumper wire Tony

[Bull Bar Cowboy]

Hmmmmmm …… good effort JU but I don’t think that universal series motor theory quite works out that well. IIRC the HP figures for these motors are input numbers, and I seem to remember that they are at best only 60% efficient. The things I can say for sure is that when the motors get exceptionally hot then their efficiency will fall.

With regard to Jim’s experience, I would only expect the motors to get exceptionally hot when they are being worked hard (I guess you need to find a bigger hill Jim !)…… and then I would expect the temperature to rise exponentially due mainly to heat soak, but other factors will also have a big influence.

I would be interested to know how Jim selects the motors to get a matched pair, because on the surface it would appear that any mismatch will cause current hogging by one motor………… however, as the current hogging motor got hot (and its efficiency dropped) then it would most likely balance with the other motor…… almost like a see saw effect. However, the current hogging (and yes, that is an acceptable technical term) will also give a speed variation between the motors.

Yes, I also like this thread…………… its not often that we can get down into putting some real effort to decide exactly what’s happening.

PS. This needed some smilies, but they don't seem to be working ?

Ian

[Daan]

forgetting the heat generated, or the current required, one of my prime concerns is weight; so jim my question is how much does a modded 8274 with twin motors and bigger drum actually weigh? And how much have you added on top of this in terms of added batteries, alternators, cables and relays? (not having a go at your setup, just interested).

Daan

[white90]

15-20kg tops for a twin motor inc cables and contactor

no more batteries required over a normal twin battery set up with a decent alternator.

[Shaun D]

Just got to put my tuppence worth in

To introduce myself: I'm the one setting up the test equipment to do the electrical tests on Jim's new winch.

All the talk about current draw for this setup is fine, if a series wound motor was purely resistive, but it's not. It posesses inductance which is something any wound item (for that read field windings and armature windings) has.

(Stick with me here I'm trying not to get too anoraky but I think this is important.)

First an inductor has the effect of trying to prevent rapid changes in current flow, secondly an inductor is also an electromagnet, has to be really or an electric motor just wouldn't work.

The effect with a series wound motor is this:-

1.The motor is switched off doing nothing.

2. Power is applied, current starts to flow.

3. The current ramps up (it would ramp exponentially but other effects come into play), it does not jump instantly to the short circuit current of V/R.

4. A very strong magnetic field is rapidly developed in the field windings, this is where the energy rushing into the motor goes first.

5. The same current of course goes through the armature where another field is developed, these two fields interact and the motor starts to revolve.

With me so far? not asleep yet? It gets worse.

6. With the motor now revolving the armature starts to behave like a dynamo and a voltage is developed that tends to cancel the battery voltage and the current starts to fall (with a permanent magnet motor on no load the dynamo voltage practically matches the battery voltage and the current drops to practically nothing).

7. As the current starts to fall the field strength drops, and so the dynamo voltage is reduced, therefore the motor continues to speed up, this is practically a vicious circle and with no load a perfect series wound motor would rev to infinity. In practical terms a series wound motor can rev to destruction.

8. If the load is increased the motor slows down, the dynamo voltage is reduced and current rises, the motor makes more torque, but also the field strength increases and the motor slows down. It's not so much the load that slows the motor but the increased field strength.

It is usually easier to visualise a permanent magnet motor first where motor current is V(bat)-V(dynamo)/motor resistance, and then think about how this affects the field strength, with a weaker field trying to make the motor rev faster.

How does this affect twin motor winches?

Inrush current will be quite a bit higher, possibly double but we're not sure yet but I'm sure they won't be as big as the scaremongers say .

When they're revolving things change, if you think of a motor as a way of changing current into line tension then for a single motor winch current might be for example 200 Amps, for a twin that would be 100 Amps per motor the field strength would be half, the speed would try to double but before this happened the dynamo voltage would reduce and current would increase (we're working faster, the extra energy has to come from somewhere) and I would think the current would settle somewhere between 200-400 amps all other things being equal.

Regarding putting 24V on 12V motors, the limiting factor of power output is the rated current, therefore twice the voltage is twice the effective power not (half the square) in my opinion. The other limits are overspeeding and commutation problems causing brushgear overheating. Motor life is going to be shorter of course but in practical terms you have to make a trade off.

All I know is, at the end of that biiiiig pull the motors were barely more that tepid, I would not even have called them warm, listen to the motor pitch on that final pull over the top, it had a savage lip on it, it doesn't show on that camera angle unfortunately, I think a single motor winch would have been nearly smoking .

This new winch is very impressive when you see it working in real life.

Waiting to be shot down by a professional electric motor designer .

Shaun.

[simonr]

Good bit of kit Jim - and a good price (I probably have a good idea what the setup costs are - rather you than me!).

Not a professional motor designer - but - have a degree in E&EE (try to keep it under a bushel though).

The efficiency of a series wound (universal) motor drops to zero when stalled and is zero when free-running, unloaded. Peak efficiency (and that's only 66% or so) is somewhere in the middle. The motors are clearly not that stressed on the video and are probably a lot closer to their peak efficiency than a heavily loaded 12v single motor.

I would suggest that on such a climb, the 24v setup will generate LESS heat than a similar 12v. If anything, it needs less cooling than a 12v in the same conditions.

The flip side of this is you can load it up such that the efficiency drops to the point where you are having to dissapate many Kw of heat and could cook the motors very quickly. With a 12v setup it would have stalled long ago and you would have given up.

Being aware of this is half the battle won. Having temperature monitoring in the cab and potentially additional cooling is the other half (so long as you pay attention to it).

Paul W IMHO has approached the problem in the most sensible way possible by covering both bases.

So, I'm agreeing with Shaun in a less long winded way.

Si

[dollythelw]

Im intreagued about the effects of unbalanced motors working in mechanical tandem

should prove and interesting test - what format will it take? include a life expectancy?

[will_warne]

For no reason other than boredom I'm going to do some maths:

P = I²R

I = V/R

So if R is constant (Motor winding resistance*) when you double the voltage you double the current, so the square goes up an f-load

Plucking numbers out of the ether, assuming a 4.6HP motor is = 4.6 * 750 = 3450W of electrical consumption @ 12v which is 287.5A flat out. That gives us the resistance of the motor, R, as 0.042 (ish) Ohms. You can begin to see why clean connections, good solenoids and big cables are important as it doesn't take much poo to give more than 0.04 of an ohm's resistance

Aaaanyway, we have a motor with R = 0.042 and we stick 24V through it:

V/R = 571A

571² * .042 = 13694W = 18hp

This is all lovely in theory as it looks like you're gaining a heap of power for not much effort. But this is maths not the real world. Those motors are going to get hot, and with 24V pushing the current through they can get a lot hotter a lot quicker - the electrical input power has been squared, but if output power doesn't rise accordingly all that extra energy has to go somewhere.

Assuming a motor may be ~80% efficient, that means it needs to dump ~20% of the power input as heat. At 12V that's 690W (so about one toaster's worth ). At 24V it's 2739W :blink: you're gonna need some serious cooling on that puppy.

I don't have Si's knowlege of electronics but I had a thought about this last night, FF. Assuming the same conditions, the twin motor setup means load on each motor is half what it would normally be with a single motor so current is half as the motor only has to do half the work (P = IV). Therefore you're heat loss through P = I2R will theoretically be quartered compared to an equivilent single motor setup. Is this right or am I talking ****???

[FridgeFreezer]

For the same load, if you spread it across two motors yes you will quarter the electrical power dissipation so they won't get as hot as a single for a given pull. That's keeping with 12v and assuming you are not going to put more load on the winch than you did with one motor. In reality of course where you might've had to stop and double-line it you will just pull single-line and load both motors up as much as ever.

Upping the voltage means that when you get both motors under a decent load the heat generated could be four times that of the 12v's. The crunch is that if you never load it up too much (perhaps it's powerful enough that it won't have to work hard?) it won't suffer that problem. If you *can* get it near the top end of its load capacity then who knows?

Oh yes and remember:

This is just in theory!

Once those winches start being used (and abused) in anger (or properly tested as Jim is due to) it's the only real way we're going to be able to compare results.

The thought has just occurred to me - the video was of a non-bogged vehicle up a 60 degree slope, even if it was 90 degrees the winch would not have to pull more than the vehicle's weight (~2t? = ~4500lbs) as it's rolling/assisting and not bogged. Assuming the setup is more than capable of 8-9k you're only operating it at half of its max load, which means no it wouldn't get hot at all compared with having to pull 8/10/12k (what IS its new design limit?)

[D9OSV]

Im intreagued about the effects of unbalanced motors working in mechanical tandem

should prove and interesting test - what format will it take? include a life expectancy?

It really is not a problem as the winch and motors find there own happy existance (Hence why an eletric winch travels slower or faster under load)

Remembering this, the motors find there own happy balance and so long as the motors are of the same type and approx condition, no problems should occur.

To put this to the test we have in fact been fitting standard motors, bowmotors and xps to together to try to force a failure, we have not as of yet, had one fail (Although i'm sure it will happen)

However, i would like to point out that this is not recommended. But we have to try it, and we will keep carrying out extensive tests to force problems so that we can fix them.

Although this is very much a finished product, please do not expect us to sit on our laurels (Fat chance!) We are already working on ways of improving the power systems to these fine units, and hope in the future to be able offer more than just the current power packs and motors available

But again this year we have proved these to be winning units with our winches featuring in the top three of every single large event in the UK, along with many top three finishes in Europe, and at least Four top three finishes in Austrailia in 2006 alone. It's a record we really should promote, however i'm a modest sole and find it sometimes a little vulgar.

However i would like to point out, that on the Channel hopping Challange in France just before Christmas, sponsered by Alfred Murray Ltd(Mr Type 'R') A (Belgian) vehicle shod with one of our single motor units won the event, and a (British)vehicle with one of our single motor winches came Second, and a (Dutch) vehicle shod with one of our twinmotor winches came third............

Not a Type'R' in sight.........Sorry could not resit that one

I'm not saying it proves anything, but it's one hell of a record.

I'm not trying to flick this thread on it's head, but i do find it strange that a unit such as the Type'R' seems to have enjoyed so little success in it's early days, i am sure this will change, but it is strange as i believe it is a very good piece of kit.

Kind regards

Jim

[Bush65]

I like the mechanical design improvements of this new top housing.

The new pinions are now supported by bearings on both sides, instead of on an overhanging motor shaft. That alone is much better for the gears.

And I imagine the intermediate shaft has better bearings than the poor needle roller bearings that Warn use.

I enjoyed the discussion on the motors.

I have another question, slightly off topic regarding the xp motors, for Shaun, Simon or someone qualified. These motors are marked parallel series wound. Is this different to the other motors used by Warn? And how does that affect winching applications.

When people here in Aus first started running these 12V motors with 24V, they found it better to arrange them to use 12V when spooling out (common practice to power out because free spool sucks on 8274's).

Regarding the debate on power from 24V vs 12V, I suggest you run a simple trial to determine output power (the only power that matters here).

Now power is the time rate of doing work. So what I suggest is to take a winch slope that will remain reasonably constant.

Then, use a stopwatch to measure the time to winch (no drive assist allowed) the same vehicle between 2 set points (establish the points so the winch is up to normal speed). Average the times for say 3 to 5 pulls, using both 12V and 24V. Allow time between each pull, to cool the motor/motors and charge the batteries to the same level. Probably have the engine stopped so that 24v alternator vs 12V alternator is not an issue.

The amount of work done between the 2 points will be constant, so comparing the time will give comparative output power.

[dollythelw]

It really is not a problem as the winch and motors find there own happy existance (Hence why an eletric winch travels slower or faster under load)

Remembering this, the motors find there own happy balance and so long as the motors are of the same type and approx condition, no problems should occur.

To put this to the test we have in fact been fitting standard motors, bowmotors and xps to together to try to force a failure, we have not as of yet, had one fail (Although i'm sure it will happen)

why were they falling over in Argyle? was that purely the casing issue? Im not being awkward and Im not partisan, I just want the toughest most reliable solution I can get, leccy or hydro I dont care - but Im not selling one solution or the other so I dont have a vested interest

However i would like to point out, that on the Channel hopping Challange in France just before Christmas, sponsered by Alfred Murray Ltd(Mr Type 'R') A (Belgian) vehicle shod with one of our single motor units won the event, and a (British)vehicle with one of our single motor winches came Second, and a (Dutch) vehicle shod with one of our twinmotor winches came third............

2006 everyone got whupped by Per in a ratty old Zook with a single bog standard low line non-8274 winch (Come up IMS?) - not a definitive test but it was fun to watch

Although this is very much a finished product, please do not expect us to sit on our laurels (Fat chance!) We are already working on ways of improving the power systems to these fine units, and hope in the future to be able offer more than just the current power packs and motors available

so you've already done the testing? cool - how did it get on in terms of load and lifespan?

I'm not trying to flick this thread on it's head...

maybe a superstar driver is needed - or maybe they suit longer raid type events where spares arent quite as easy to source? leccy winches for uk style comps are pretty much ideal so no arguement there, but it does seem theres a lot of people fitting hydros these days... not sure why but they do seem to site reliability as an issue.

theres always the Kolar Peninsular raid - if it konks out there you leave the car behind, now that would be a good test

[Mark90]

Regarding the debate on power from 24V vs 12V, I suggest you run a simple trial to determine output power (the only power that matters here).

I disagree. The input power would also be of interest to show the efficieny of the motors. This may well be of significance in you suggested test with the engine off as one setup may drain the batteries more than the other.

[Daan]

RFC? its a long walk home if your winch fails and the temperature is around 30 deg c to begin with.

Something else crossed my mind; If the objective is more motor, cant you just fit a bigger motor instead of two? usualy if things happen on a greater scale, efficiency improves. In my mind a bigger motor would therefore be better than 2 smaller ones. Or is it a supply issue?

Daan

[FridgeFreezer]

Looking at Isakara's website they stop at about the 4kw point for 12V and the 11kw point for 24v, I'm guessing there's a limit you hit where it's no longer practical to use such a low voltage / high current as most people designing a drive system would up the volts to keep costs down, after all batteries only come in certain sizes and by the point of a system using that much power most would be paralleling several batteries to keep up - at which point you may as well reconnect them in series and drop your amperage, and hence wiring and switching capacities, right down instead.

It's only the fact that most vehicles are 12v that ties electric winches to being 12v, otherwise something like 48v would be far more sensible and efficient. I believe modern cars are going to start coming with ~42v electrics for this reason, ISTR BMW are already doing it on the 7's.

[Bull Bar Cowboy]

It really is not a problem as the winch and motors find there own happy existance (Hence why an eletric winch travels slower or faster under load)

Remembering this, the motors find there own happy balance and so long as the motors are of the same type and approx condition, no problems should occur.

To put this to the test we have in fact been fitting standard motors, bowmotors and xps to together to try to force a failure, we have not as of yet, had one fail (Although i'm sure it will happen)

However, i would like to point out that this is not recommended. But we have to try it, and we will keep carrying out extensive tests to force problems so that we can fix them.

This is excellent R&D practice.............

I guess this was my only concern .................. about how the motors behave if they are not balanced in terms of their electrical and mechanical properties. I guess that as they are both driving, then the balance will be achieved mechanically, although given slight electrical differences the current drawn by each motor will be far from identical ( and this will be more apparent when driven from 24V)............ but I don't see that it really matters too much, other than when the going gets tough and the motors begin to quickly heat up.

I also like the idea of inbuilt redundancy ............... I guess that if one motor fails then the other will be able to carry on regardless, taking the full load.

Although this is very much a finished product, please do not expect us to sit on our laurels (Fat chance!) We are already working on ways of improving the power systems to these fine units, and hope in the future to be able offer more than just the current power packs and motors available

I guess it would be good to implement electronic braking on the motors .................or do you get less overrun with the twin motor set up

I'm not trying to flick this thread on it's head, but i do find it strange that a unit such as the Type'R' seems to have enjoyed so little success in it's early days, i am sure this will change, but it is strange as i believe it is a very good piece of kit.

Kind regards

Jim

Type 'R' in an OK (ish) product .......................... but I strongly believe its implementation and marketing has not helped the product to achieve its true status

Again I am not a motor design engineer, but like Si I have all the right bits of paper ..................... my skills are in wide area radio system design (Public Safety).

Ian

[D9OSV]

why were they falling over in Argyle? was that purely the casing issue? Im not being awkward and Im not partisan, I just want the toughest most reliable solution I can get, leccy or hydro I dont care - but Im not selling one solution or the other so I dont have a vested interest

2006 everyone got whupped by Per in a ratty old Zook with a single bog standard low line non-8274 winch (Come up IMS?) - not a definitive test but it was fun to watch

so you've already done the testing? cool - how did it get on in terms of load and lifespan?

maybe a superstar driver is needed - or maybe they suit longer raid type events where spares arent quite as easy to source? leccy winches for uk style comps are pretty much ideal so no arguement there, but it does seem theres a lot of people fitting hydros these days... not sure why but they do seem to site reliability as an issue.

theres always the Kolar Peninsular raid - if it konks out there you leave the car behind, now that would be a good test

Thank you for bringing up Argyle

I will go through team by team.....

The winners Pete Whitman and Byrn Hemming...

Both using the early converted tophousing twinmotor 8274's, Byrns never faltered or halted on the entire event and is still running strong to this day

Petes suffered a damaged rear motor drive gear due to flicking the winch switch, this gear was replaced and the winch continued to the end, and still runs today with no further problems.

Second place, Justin Dean and Willie Davenhill

Justin Dean was agian running a converted top housing twinmotor 8274 , however on the final day the drum split due to a faulty tig weld on the drum, purely unfortunate.

His partner runs a standard 8274.

Third place

Myself and Paul Wightman

Both using converted top housing 8274's, first time anyone in the uk had used 24volts through 12volts competitively. Both winches faultless first day apart from battery (Lack of) problems towards the end.

Day two, The upper gearbox bearings (Standard orginal equipment) on my own winch destroyed themselves at lunchtime (This was a new winch, old style converted housing) this forced us to retire. Paul swapped back to a large single motor setup as a larger alternater was required. Pauls winch still runs the Twinmotor steup and with a larger alternater has suffered no further problems.

The Dutch team of RP and Jo Laeven both running twin 8274's unfortuantely retire early day one due to RP breaking a cam belt. RP recovered his vehicle as fair as the batteries would allow with no problems (Can't do that with Hydraulic) and Jo played the rest of the weekend with no problems.

Despite the Teams running Type 'R' winches finishing the event, they failed to make a large impression on the event or the leader board, with the highest placed being joint fourth (Still a remarkable undertaking).

So Yes, there were failures, but every team was already breifed, and told NOT to flick the switches, These teams have helped us to produce the all NEW top housing, to erradicate those faults, and now, flicking of the swich all though not recommended is allowable with the new unit.

The teams that ran our Early system have all been offered a full refund againist the price of the ALL NEW top housing to say 'Thank you' for there help in testing the theorys etc...

How many would do that???

So though many went for our throats after Argyle, again i'll keep quiet, and let the score sheet do the talking

Also i believe you mean 2005 and not 2006 Dolly, in reference to Channel hopping competition?

As the scores i quoted are from December 2006

I'm not saying our winches are the best solutions for everything? But i do believe, as Dolly points out, that they will take a lot of beating where ever they are found

Kind regards

Jim

[will_warne]

When people here in Aus first started running these 12V motors with 24V, they found it better to arrange them to use 12V when spooling out (common practice to power out because free spool sucks on 8274's).

This is something I've thought about too mainly because lowering out would be very fast with overvolted motors. I'm also looking into the possibility of being able to apply power in 2 stages; push the switch so far and get 12V, push it further and get 24V. Not that 12V would be used often but it would allow for more contolable lowering out and more accurate control for very technical work when a quick flick of the switch with 24V might be too much. I've just got to work out how to make the wiring work!