Neu Motor Running Hot
 

Running a Neu 1512 2.5D on a Losi 8ight geared at 14T/46T (44mph calculator) with 5S 5000mah 25C/50C batteries and MMM ESC. Batteries are only around the 95F - 112F and MMM is 100F - 125F (measuring through the gaps for the heat sink) and the motor gets up to 145F - 165F (it is currently winter here in Australia although no snow etc. still warmish). I am running standard diff fluids for the Losi 8ight Roller F - 3000 C -5000 R - 2000 and measuring it with the Duratrax Temp Gauge. I read on here in the FAQ section that usually when just the motor is hot it is undergeared but wouldn't really think you would need to gear for more than 44mph. Can changing the diff fluid here at all?

I would gear up. Maybe I am putting something wrong in the calc but with 14/46 gearing a 1650kv motor and 18.5v I am only coming up with 36mph.

I ran a 1512 3d(1700kv) in my 8 and believe I was running 17/44.

1512 2.5D is 2050KV
http://www.neumotors.com/20061222/1500_series_.html

I'd honestly try gearing down first. If that doesn't help then go up.

DRIFT - this is sounding very much like the same problem I am having with my buggy that I just posted about.
http://www.rc-monster.com/forum/showthread.php?t=13040

What tires are you running? I noticed my problem seemed to be worse when running the Moab 1/8 buggy tires compared with others - there seems to be a 0.5" ballooning effect going on with these tires which will throw the overall gearing off when at WOT.

Also - where and how are you running? Are you racing on a track or bashing around in parking lots/dirt/grass fields?

sorry I was thinking 1515 2.5d

Those are normal temps, that is what I have been getting for the last two years and my motor runs great. I race every weekend all year round.

My concern is not about 165*, it is when I see the temps going over 170 and climbing up to 180. I don't want to risk demagging a $250 motor.

Those are not bad temps. I would put heavier diff fluid in the center maybe, like 7k or 10k (I like 10K in mine).

I get 170 -180 on my Feigao 8XL all the time. And it's been running like a champ for over two years. I think you will be ok with 145 - 165 temps on your Neu.

Yes, but what will he do when the weather starts getting warmer? He said it was winter. I would have to agree and say you should gear down, and if that doesn't make it better than gear up a bit. But I agree, I would never run a neu motor if its getting that hot all the time, to much money to risk.

Check your timming setting on your ESC.

On a "d" wound motor, your timming should not be higher than 10 degre. 0-5 is the best. Higher and it'll heat up.
On a "y" wound motor, you could go over 10 degre

David

David

do you know the theory behind that is? this is the first time I have heard it and I am curious.......

Not sure where you are running your car, but those temps are pretty consistent for a Neu under race conditions. Nothing to worry about at all.
You can play with the gearing and check the timing settings on the MMM to see if you can shave some a few degrees off, but those temps are more than acceptable. I keep all mine set to lowest and everything runs great. I pretty much average out about 140-165ish after a hard race. Once you start getting up to 180+ you shoudl be really concerned. I believe the official danger zone is 200+ degrees.

Recommended by Neu (from another forum I believe), as I have heard this as well. Also the instruction sheet that comes with the Neu motors (you do read the instructions right?) says low timing.

exact, on the Neu website

The temps are while running at my local track. I am using the standard Losi XRT (or something like that) tyres.
Here is a shot of the MMM specs
http://www.geocities.com/athowells_r...ngs_190608.jpg

I didn't get no instructions with my motor.

Me neither.

If the value "10" on the motor timming case is the value giving in degree, i find it little high for a "d" motor. Try to put it at 0, or if you have the option "automatic timming" as on the MGM controller, put it on automatic.:wink:

Thanks, ill give that a try, the 10 is what the ESC was set to and it said normal so I just left it at that

I too was beginning to wonder where my destructions were.

Luckily I'm not the only one.

Might set it at 3 for now since it was set at 10 before and wasn't running crazy hot, see how it goes from there and still nothing change try 0

in my experience with other motors, the timing doesnt seem to do much at all except raise temperatures. would you be able to tell the difference between 3 and 0?

That's interesting to know about the timing. Let us know what the difference is temperature wise when you drive it on the track again.

I would agree with that...:yes:

So what was the outcome drift. Did the temps come down? I am very tempted to copy your setup.

Well just got back from the track. With it a 3 degree the motor still got up to 170F and the ESC up to 128F, battery 95F - 110F. Im now going to set the timing to 0 and put the larger 15T pinion in instead of the 14T which will raise the top speed to 47mph. My local track is fairly large. I have some thicker centre diff fluid (10000, standard in roller 8ight is 5000) coming to. If that doesn't change the temp I might look at putting a fan behind the rc box which will flow air straight onto the motor and try to work out how to go more air flow to the motor. This is a great buggy to drive and once I work out how to get the motor to stay cool, im laughing

i ran my xt8 at the track yesterday , and i ran 4 packs, i had been running 0 timing but i changed it to 12, my temps went from 165 down to 155, but i was on a track and not wot bashing, but i think it helped.......:neutral:

1515 1y , 4s , 17/48

Well changed to 15T pinion and timing to 0 and went down to the track and after 8 minutes again same temps as above. I thought it was running better as I perfered the 15T over the 14T but after brining it in to check the temp. I don't think I mentioned in the 1st post that I have a front cover in front of the motor to stop debris getting in the holes.

Would changing the centre diff fluid help much? See most people that run Brushless 8ights run 7000 or 10000 in the centre diff.
My track is pretty dusty (fine dirt) and don't really want to remove the front motor cover but might have to. Was looking at putting fly screen in front of the motor. Anyone tried this before?

Well I tried gearing down. Went down to a 13T and temps did drop. ESC was running at 105F, Bat 96F and ESC was around 155F - 165F and that was after 15 minutes of racing around the track. Couldn't test no more as battery was starting to run slow. It was the same battery I have been using all day. I found myself using WOT alot more with the 13T over the 14T & 15T but it temps stay around there I wouldn't mind. I only have a 13, 14 & 15T pinion so can't really test out other sizes but don't see why I would need to anyway. Charge battery up tonight and go out tomorrow and see if temps stay down. It is also late afternoon here so temps aren't as high as what they were earlier in the day

Normally you can see if they are putting all the power to the front wheels fairly easily. How are the front tires doing. If it is chewing up the front tires definitely up the diff fluid weight. I just bought my first 1/8th buggy and I can't wait to get it converted. Driving it as nitro was good fun when it worked.

(For what it worth DB)
I use 30,000 weight in my center diffs, I also know that MetalMan and others do as well with great results..

Yeah, the front tyres balloon when i give it some throttle.

>Would changing the centre diff fluid help much? See most people that run Brushless 8ights run 7000 or 10000 in the centre diff.

Increasing the diff fluid wheight will decrease unloading to the front tires which act like a big slipper. Thus traction normally will increase which results in an increase in amps too (as more power can be transfered to the ground). Higher Amp peaks will result in a hotter motor.

Very loose centerdiff = less amps, cooler motor

Those were my findings using an eagletree datalogger and comparing a center diff filled with grease, 10000 and 30000 silicone oil.

What about using fly screen against the motor & a piece of airfilter foam between screen & the motor mount.

Tekno are making Neu motors that are sealed, how is this affecting the heat dissipation?

I am thinking a screen that is small enough to keep out dust would get clooged up pretty quick, I would think that a small piece of foam material and some oil like they use for a K&N filter for a 1/1 size car

I started running my Neu's open. I used to just put some electrical tape on the front and used Mike's rear end cover. I find running it open helps temps a bit and I haven't had any problems with dust and rocks. I know others that do the same. I just blow it out with air after a few runs.

You will be hard pressed to keep your motor temps below 150 if you are racing. 150-175 is typical and nothing to worry about for track duty. I rarely ever get above 125 bashing though.

Ill experiment more when I get the diff fluids. I was looking at maybe using a Outerwear filter over the motor
http://www.amainhobbies.com/product_...ducts_id/16582
http://images.amainhobbies.com/image...20-2270-01.jpg