Neu heat problems - RC-Monster Forums

ogrfre01 · **Neu heat problems -** 08.25.2008, 01:08 AM

I just got a Neu 2.5d/s and put it in my converted Losi 8ight. The other stuff is:
-MMM (V2)
-Polyquest 4S, 5000mah
-Gearing 14/48
-Futaba 2,4Ghz, Futaba S9451

I ran it yesterday and it gets really hot..... the MMM made a thermal on me! after 30 min on a track...... and the motor was even hotter...... i could´nt believe it

I had someone else checking my setup and he said.... hmmm, shold the motor shaft be so far out in the back?

So my question is if this is normal or is the motor defect (see picture below)?

Note that this is BEFORE i even mounted the motor in my buggy:

DRIFT_BUGGY · 01:16 AM

That setup should be fine.
What is your ESC settings? Make sure the timming is set to 0
Also, what diff fluid are you running? If it is still the standard diff fluid you will need to get thicker fluid. I run 5000 - 10000 - 3000 but most others run thicker. I also have that motor in my 8ight but am running 5S with 13T pinion and 46t spur and my temps for the motor are around the 160F mark adn 115F with the MMM. What spur are you using since you are running 48t?

ogrfre01 · 08.25.2008, 01:18 AM

Timing is "0". I dont see how the diff fluids will change the temp in the electronics that much? im running 5/5/2 and i really like how it handles

lincpimp · 08.25.2008, 01:27 AM

The problem with thinner fluid in the center diff is that it unloads too much and you end up over-revving the motor. BL motors really do not like to be revved high with little load, it causes alot of heat and possible motor damage. I would try to 10k fluid in the center diff. You may want to send the motor back and have them check it too...

jnev · 01:29 AM

This is only a guess, but maybe the oil in the center diff is too thin allowing the front wheels to spin too fast possibly over revving the motor...?

EDIT: Linc beat me to it, but I was right on the answer at least.

DRIFT_BUGGY · 02:11 AM

Yeah, 10k is usually the thinest to run in the centre diff. When you are flying down the straights, does your front tires balloon alot compaired to the rear?

ogrfre01 · 02:15 AM

Quote:

Originally Posted by DRIFT_BUGGY

Yeah, 10k is usually the least amount to run in the centre diff. When you are flying down the straights, does your front tires balloon alot compaired to the rear?

Not allot..... i guess i can try 7 el 19k in the center diff...... i still think it is strange that this could cause the motor to overheat.... and im still not a novice to electronics (electronics engineer)

ogrfre01 · 02:16 AM

First, thanks for the replies

I really dont think that thinner fluids in the diff could cause the motor to overheat this much...... i can accept some more heat but not this much? I have´nt had this kind of simular problems with my previous Medusa.....

Also, over revving, with 4S...... is that really possible? To make sure, overrevving, please explain so i understand this correctly.

Now to my primary question so you remember this, should the motor shaft stick out that far or not?

lincpimp · 08.25.2008, 02:15 AM

Quote:

Originally Posted by ogrfre01

First, thanks for the replies

I really dont think that thinner fluids in the diff could cause the motor to overheat this much...... i can accept some more heat but not this much? I have´nt had this kind of problems with my previous Medusa.....

Also, over revving, with 4S...... is that really possible? To make sure, overrevving, please explain so i understand this correctly.

Now to my primary question so you remember this, should the motor shaft stick out that far or not?

You may have a loose shaft (no need to make any jokes guys...) not sure. I bought a 1515 with that problem and sent it back to neu, who fixed it for free...

No load, high rpm running of a motor can cause damage. The kv rating of the motor is figured out under load, so without load the motor can easily spin past 100k rpm. These motors also have a rpm window of operation that they are effecient in. Spin the motor too fast and the effecientcy drops and the heat goes up. Give some thicker fluid a try and see how that does. Or run it some more and see if the shaft moves.

ogrfre01 · 02:30 AM

Quote:

Originally Posted by lincpimp

You may have a loose shaft (no need to make any jokes guys...) not sure. I bought a 1515 with that problem and sent it back to neu, who fixed it for free...

No load, high rpm running of a motor can cause damage. The kv rating of the motor is figured out under load, so without load the motor can easily spin past 100k rpm. These motors also have a rpm window of operation that they are effecient in. Spin the motor too fast and the effecientcy drops and the heat goes up. Give some thicker fluid a try and see how that does. Or run it some more and see if the shaft moves.

Thanks for the reply, I´ll try some 10K diffoil in the center diff.... also i will try running it without the rear cover just to make sure that if the temps go up high again there is something wrong with the motor.
I will also check every connection, solder, bearings...... i dont like temperature-related-problems

I chose the MMM and the Neu just to make sure i wouldnt have any issues with temeperature. Ironic

I mean this setup runs hotter then my previous MM/fan+CCBEC+Medusa so im not that happy about it.

DRIFT_BUGGY · 08.25.2008, 02:27 AM

Do you know what the temp was?

ogrfre01 · 02:45 AM

Quote:

Originally Posted by DRIFT_BUGGY

Do you know what the temp was?

the MMM makes a thermal at 90 degrees centegrade right? the motor was atleast that hot also.....
I appriciate all hints so i can determine where the problem is.
(Im not great with spelling, it´s been a long time since i was in school using english *lol*(sweden))

DRIFT_BUGGY · 08.25.2008, 02:45 AM

Yeah, well gearing at 14T/48T makes it around the 35MPH mark which should be safe. My motor shaft seems to be sticking out that far aswell

ogrfre01 · 03:01 AM

Quote:

Originally Posted by DRIFT_BUGGY

Yeah, well gearing at 14T/48T makes it around the 35MPH mark which should be safe. My motor shaft seems to be sticking out that far aswell

Ok, that sounds like good news... I am worried that there is somthing wrrong with the motor but im hoping that it is something else. I have some things to check when i come home after work today....6 hours left

Nephre · 06:55 AM

This is quite a mystery since Ogrfre01 bought the motor from me and I didn´t have heat issues with it. Had it in my mbx5 prospec, ran it with 4s lipos, MMM and geared 12/46. Temps was about 60-65C/140-149F which I would say is far from to high.
Awsome motor but I don´t know why it´s heating up like this now when it didn´t do that to me.