Mamba max getting HOT fast! - RC-Monster Forums

rootar · **Mamba max getting HOT fast! -** 11.27.2007, 02:06 PM

i dont have a temp gun but i can only hold my finger on the heat sink for 3 secs after only running for 2-3 minutes, I installed the CC UBEC last night and it didnt help the problem, still very hot, its 45 degrees outside and the motor (Feiago 9l) and mambamax temps are WAY up there, my battery (3s 5000 maxamps) is not even warm at all, its almost as cold is the temp out side. Are these kind of temps normal? im gonna get a temp gun asap but what can i do to get it to run cooler? im taking the plugs to the motor off and direct soldering them, maybe this will help and little bit with the low speed cogging but what about temps?

glassdoctor · 11.27.2007, 02:25 PM

Could be the gearing... it's in the LS10? That should be ok...

MetalMan · 11.27.2007, 02:36 PM

Just an idea to throw out there, is it possible that the screws holding the motor to the truck are penetrating the motor windings? That would explain the heat, and the cogging.

Happywing · 11.27.2007, 03:10 PM

You did disable the BEC on the MM, correct?
What is your gearing?
What surface are you running on?
Any fans on the MM?
Do you brake a lot?
What are your MM settings?

rootar · 11.27.2007, 04:02 PM

Quote:

Originally Posted by MetalMan

Just an idea to throw out there, is it possible that the screws holding the motor to the truck are penetrating the motor windings? That would explain the heat, and the cogging.

DANG i bet thats what it is! i thought i needed to trim those some because i knew theyd be close but they could be touching.

-i did disable the mm bec
-gearing is 13/54 its only geared for like 33-35 mph (low compared to everyone else)
-smooth concrete parking lot for testing
-no fans, a rcmonster heatsink on the motor thats all
- the mamba max is setup right according to the book (high start power and all for the 4wd and heavy truck)
-truck is just barely under 5 pounds

ill check and cut my motor screws off 1st and then see how it goes from there.

lincpimp · 11.27.2007, 04:17 PM

I did the same thing with a feigao, screws were too long and it did heat up very fast, plus my battery almost puffed! I tried shorter screws, but the damage was done and I had to replace the motor. I did it to a 7xl, but I am sure all of the motors would react the same. Hope that you did not kill the 9l, it is a great motor for that application!

MetalMan · 11.27.2007, 05:02 PM

Quote:

Originally Posted by rootar

DANG i bet thats what it is! i thought i needed to trim those some because i knew theyd be close but they could be touching.

ill check and cut my motor screws off 1st and then see how it goes from there.

It shouldn't be a problem if they are just touching. The windings have a coating on them (epoxy, I think), on top of the normal insulation they have. So to get to the bare wire you'd have to push past the epoxy and thin wire insulation. But it's very possible that when the screws were tightened down the wires were punctured.

neweuser · 11.27.2007, 03:50 PM

Just a question, how hungry are the 9l's? That could be an issue for the MM too?

rootar · 11.27.2007, 05:22 PM

so if the screws left marks in there my motor is ruined?

t-maxxracer32 · 11.27.2007, 05:33 PM

just test the motor to see if it still works.

if it does then awsome. if it doesnt.... then you need to buy a new one.

MetalMan · 11.27.2007, 09:38 PM

It depends. If the windings have been damaged from being shorted out by the screws (assuming the screws are cutting into the windings), then the motor is done. If the screws didn't cause much current to flow through the short, then it's fine. Like t-maxxracer32 said, try out the motor (with shorter screws, of course).

rootar · 11.27.2007, 11:39 PM

Well my screws had left markings on both sides of the windings, i did cut them and tried it anyways, it didnt cog as much (still a little), it ran like a bat out of hell, but sadly you could have cooked breakfast on this thing after only a minute. the mamba was hot but i could hold my finger on it for 4-5 secs the motor burned my finger after 2 secs (I now have a burn on my index finger, sucks). i guess the motor is a goner? i didnt even bother trying direct soldering the plugs yet, i dont really want to chance puffing my brandnew battery or my Mamba max by continuing to run it if the motor is bad.....

lincpimp · 11.27.2007, 11:47 PM

Sounds like the magnet is gone on yours. Does it still have some resistance when spun by hand? If the feigaos get too hot the magnets usually demagnetize, due to their cheapness! Maybe the too long screws caused the high resistance - heat and that caused the motor to cook? Who knows, do you have another motor you can try with the combo to rule out other problems?

rootar · 11.28.2007, 12:12 AM

nope that the only motor i have/had, it smells now, kinda a burnt oil smell, mamba max cooled down really really fast after i unplugged it, it took a while for the motor.

i have the motor apart now and its definetly the rotor/magnet that smells burnt, the windings in the can right there surrounding the rotor all look burnt too. Ill try and get some pictures up. It still had a little magnet left in it, not much resistance, i spun the motor with the pinion on with my finger and it rotated 4-5 times after i let go before it stopped, when i got it from you james it would stop after 2-3 rotations after i let go.

Mike is out of stock of 9L motors could i use a XL motor of the same kv as the 9L? id like to get another motor pretty quick, if not where could i find a 9L for a decent price with FAST shipping?

lincpimp · 11.28.2007, 12:19 AM

Sounds like it is toast. If mike can't cant get you a 9l try steven at www.offshoreelectrics.com. Usually he has the motors in stock and he gets me stuff as fast as mike does. He has great customer service, and a great rep in the rc boating scene. Lots of cool stuff on his site too, mostly boat related. I like brushless boats too, so I usually use him for hulls and equipment.