Acceptable Temperatures?

[CAClark]

Ok, here is what I have in my Durga:

LRP AI Pro Reverse ESC
LRP Gt3 12x2 motor
4500mah Stickpack

Now the ESC is soldered direct to the motor. The ESC to battery now has deans connectors as the tamiya jobbies melted.

So I gave it literally a minutes speeding in the car park outside my apartment, and the motor & motor to esc wires are so hot that the cable tidy spiral stuff melted to the wires.

Is this kind of temperature normal in such a short run?

Cheers!

[Jonny_H]

What gauge wire are you using? 14 SWG, or even 12 SWG (thicker) is usually a good idea.

How hot is the motor itself? Can you keep a finger on it for a few seconds?

What gearing are you using (someone else with a Durga will have to confirm), and how much timing have you set on the motor?

[TheNinj]

uh-oh... Sounds like someone has melted yet another set of wires!

Before I put my 8x1 turn motor on mine and subsequently melted the tamiya connector to the ESC, my 17x3 motor would get the wires really hot, to the point of discolouring them. I would suggest not using any plastic wire tidy type setup as it's bound to end in tears!

Even in my Hotshot the wires get pretty warm and thats only a Tamiya sport tuned.

[JCJC]

Our first propper car, a belt drive, 4WD buggy, a Yoke MX4BC would overheat like mad, took a long time for us noobs to find the rear diff had gone, I would look at all the drive, car should roll like a hotwheels toy when the motor is not in.

[budgio]

I,m running a mamba max 4600 with a 19t pinion & 4600 stickpacks,Durga runs sweet and i had no problems in the heat at Coventry today.
Double check your diffs, i melted mine once because they were not tightened properly.

[CAClark]

Originally Posted by JCJC

Our first propper car, a belt drive, 4WD buggy, a Yoke MX4BC would overheat like mad, took a long time for us noobs to find the rear diff had gone, I would look at all the drive, car should roll like a hotwheels toy when the motor is not in.

It does roll smoothly, and I tightened the front diff a little, but that all still tuens free as well.

Originally Posted by TheNinj

Even in my Hotshot the wires get pretty warm and thats only a Tamiya sport tuned.

Yeah, but there's hot, and then there's hot

Originally Posted by budgio

I,m running a mamba max 4600 with a 19t pinion & 4600 stickpacks,Durga runs sweet and i had no problems in the heat at Coventry today.
Double check your diffs, i melted mine once because they were not tightened properly.

As I mentioned above, they diffs seem fine as far as I can tell.

Originally Posted by Jonny_H

What gauge wire are you using? 14 SWG, or even 12 SWG (thicker) is usually a good idea.

How hot is the motor itself? Can you keep a finger on it for a few seconds?

What gearing are you using (someone else with a Durga will have to confirm), and how much timing have you set on the motor?

Not sure of the wire gauge, but the motor to esc is the wire prefitted to the esc. And the design of the LRP ESC looks like you can't easily shange them, so I would assume it should be good as it's rated to motors over 10 turns.

I'll have to run it again tomorrow and then check the motor temp itself.

In terms of gearing, I have the standard spur gear, and had a 23t pinion, which this time I have replaced with the smaller one.

Cheers!

[CAClark]

Any other ideas here? I really need to get this sorted out, or indeed verify that what seems wrong to me is actually normal enough.

Cheers!

[sparrow.2]

If your solder joints are bad they will overheat too but then they usually unsolder.

The smaller pinion gear is a good idea. How long does the 4500mAh battery last? If you are running the car for longer than say 10 minutes or so in long grass it might just be overheating because of that.

Is the motors comm still ok and the brushes not worn out?

Good Luck

[CAClark]

Hey

I have no doubt my soldering is less than stellar, but that said, they did hold.

The car was only run for a minute or so, and that was up and down an asphalt car park. I'm assuming the motor should still be pretty much A1, as it is only a couple of weeks old and hasn't had more than 10 minutes running owing to a succession of things melting. I had the wiring looking pretty close to how jimmy did his durga in the review, but where the spiral bound receiver wire went over the motor, that melted where it ended up touching the solder points on the motor, although the silicone wires from the ESC don't show any signs of melting.

It just seems odd as the motor in the grand scheme of things is pretty tame as far as I can tell.

Cheers!

[Southwell]

Rubbish solder will also have a lower melting point than some like the Deans stuff, this can cause the problems, along with bad solder joints.
Also if you are running the car up and down a car park at full throttle constantly it will get hotter than running them as designed.

[CAClark]

Originally Posted by Southwell

Rubbish solder will also have a lower melting point than some like the Deans stuff, this can cause the problems, along with bad solder joints.

I have some Deans solder on order from Modelsport, but they seem to be taking a long time to get it. I'll chase them now that you have reminded me. I think the solder I have used in it's absence in regular Draper solder.

[Southwell]

Originally Posted by CAClark

I have some Deans solder on order from Modelsport, but they seem to be taking a long time to get it. I'll chase them now that you have reminded me. I think the solder I have used in it's absence in regular Draper solder.

Make sure you get as much of that solder off as you can, it's not designed for this application and i would probably say is one of the problems, the other possibly being gearing.

[Southwell]

Just read you first post properly, i would say gearing/cooling is your issue. Check the brushes, are they purple?

[CAClark]

Ok, well when I get home tonight I'll check the brush colour, but I'll also add a bunch of air holes to the intake type areas in front and behind the motor.

Are heatsinks for the motors generally worth while, or more for show? The ESC has a heatsink already, so can't do much there.

Again, with the solder, I'm a bit stuffed until Modelsport get my solder out to me

Cheers!

[jim76]

Originally Posted by CAClark

I had the wiring looking pretty close to how jimmy did his durga in the review, but where the spiral bound receiver wire went over the motor, that melted where it ended up touching the solder points on the motor, although the silicone wires from the ESC don't show any signs of melting.

from the soundss of that, you had the spiral wire resting against the motor endbell yes? so the solder tabs on the motor melted into the plastic when the motor was hot?

This may not be a huge problem as brushed motors do get pretty hot when thrashed around, and if the plastic has a pretty low melting point then that could explain it. The way to spot a major problem is as previously said the motor wires unsolder themselves, or if you notice the performance of the car drop off considerably.

Check what gearing most club racers use for your car as a good starting point. Run the wires so they don't actually touch the motor. And try and improve the air flow through the shell with cut outs in the vents and make sure there is a cut out at the rear to let the air flow out the back too.
You can also fit a small fan in the car to blow air at the motor if the problem persists.

[Jonny_H]

Right, looking at this thread I think you can work out the overall ratio, on a standard spur, by

ratio = (approx) 186 / pinion

For a 12 turn motor I'd suggest starting around 10.5 or 11.0, so that's an 18 or 17 tooth pinion. 23T is 8.1 : 1, which sounds far too tall (although tarmac gives you the best chance of getting away with it - in grass you'd definitely kill it).

Your brushes will almost certainly be purple / grey at the tips - throw them away and fit new ones, ideally getting the comm (which will also be purple) skimmed at the same time.

[CAClark]

Ok, I checked the brushes, and they look ok, not purple or grey, I'm guessing because the run time was very short maybe, so. I have put the 17T pinion back on, and have made holes in front of, and behind the motor area.

I contacted Modelsport, who have sent me scumacher solder as the Deans stuff is an ETA unknown. So I will unsolder the motor, and while at it add Deans plugs so that I can switch to the other ESC when the time comes.

I'll come back to ths thread once all that is done.

Thanks for the input so far, mucho appreciated!

Cheers!

[CAClark]

I really really need help now.

My mate let me borrow his old Yokomo 17T stock motor, which I connected up with the LRP AI speed controller. It is rated to motors over 10 turns.

It ran fine for quite a while, and seemed pretty rapid with it, but low and behold, after 10-15 minutes, it ground to a halt, and yet again, the motor wires had melted the solder and become detached.

I'm getting a bit pissed of with this now, as I can't see why it is all getting so hot. I can't entertain any notion of racing the poxy thing as it stands.

Is there some kind of 'secret' to this lark or what? Cos I'm baffled

[jimmy]

It's hard to diagnose your problem - other than ruthless driving - without seeing the car in the flesh. First time I got a 4WD buggy after I started racing (2wd) was a XXX4, and I drove it like such a nutter that I couldn't last 3 minutes. full power, full brakes, full power, full brakes etc... No car is going to survive that so lets rule that out

I use some weller radio solder from b&q so I don't think solder is your problem - if your wires are getting that hot then it's not right. I don't have the air holes on my Durga cut out and don't use a heat sink etc etc.

You've not taken the motor apart have you and possibly reassembled it with too much advanced timing? loads of advance on the motor would do this.

[CAClark]

Hey Jimmy
yeah, I realise it's not an easy thing to help with, sorry.

The motor doesn't have adjustable timing, but more over, it is the motor that was in my mates losi, and it ran just fine in that. I'll admit driving wasn't the most restrained, but the losi which is running an Peak 8x1 was being driven harder than mine, and yet the electrics were not as hot in the losi. On my Durga, even the underneath of the chassis where the alloy motor block attaches was too hot to touch.

The drive train rolls freely, and ball difs run freey as well, and the slipper looks ok as well.

Cheers!

Originally Posted by jimmy

It's hard to diagnose your problem - other than ruthless driving - without seeing the car in the flesh. First time I got a 4WD buggy after I started racing (2wd) was a XXX4, and I drove it like such a nutter that I couldn't last 3 minutes. full power, full brakes, full power, full brakes etc... No car is going to survive that so lets rule that out

I use some weller radio solder from b&q so I don't think solder is your problem - if your wires are getting that hot then it's not right. I don't have the air holes on my Durga cut out and don't use a heat sink etc etc.

You've not taken the motor apart have you and possibly reassembled it with too much advanced timing? loads of advance on the motor would do this.