Big problem, MM hot after nothing - RC-Monster Forums

supralover72 · **Big problem, MM hot after nothing -** 06.26.2007, 01:14 PM

So I finally finished everything on my Jammin. I test it, it whines terribly. I adjust the gear mesh, it doesn't whine as bad, but still bad, and then I smell a burning smell. It's my Mamba Max and it's hot after maybe 5-10 seconds of running. My Fegiao then became hot after the second few second test run with the same results. This is on my lap with no wheels, MM and Fegiao 8xl with 12 cells. I fixed one problem already which is my motor mount and batter tabs touching and sparking.

Could it be bad solder joints? Could it be the gear mesh? I'm clueless.

I'd shoot a video but I don't want to screw up my MM. Thanks for the help.

BrianG · 06.26.2007, 01:30 PM

Hmm, that IS odd. How free is the drivetrain? With the pinion removed, there should be very little resistance.

You'd have to have one heck of a tight gear mesh for it to cause that much heat. I always use the paper trick; put a piece of regular lined notebook paper in between the teeth and then set the mesh fairly tight. Then, turn the gears to get the paper out. If it slides out the mesh is too tight. If the paper tears badly, the mesh is too tight.

supralover72 · 06.26.2007, 01:37 PM

The drivetrain is free and the only noticeable resistance is the silicone diff fluid, and I already did the paper trick and it was perfect. I'm clueless still.

Thanks though.

BrianG · 06.26.2007, 01:40 PM

Try removing the pinion from the motor and running it freewheel. But only use about 1/4 throttle! You don't want to rev very high with no load. The motor should get warm after about 30 seconds, but the ESC and batteries should stay cool. If the ESC or motor get hot quickly, you definitely have something wrong.

supralover72 · 02:34 PM

When I did this, The motor and the esc were both pretty cool, but the esc was 5 degrees hotter. Here were the final results:

ESC: 90.6

motor: 85.5

EDIT: Ok, fixed one major problem. Found out how to disable the BEC and did it. Seems like it helped out with the heat issue a lot. The thing I'm worried about now is the whining/grinding. It also looks like I have a bent rear center universal, but I can't tell for sure.

MetalMan · 06.26.2007, 03:29 PM

I was going to say, it sounds like your BEC is enabled (whether you were using an external receiver/servo power source or not). A BEC that is overheating (which can be caused by 12 cells on a high power servo turning MT tires) will cause the entire ESC to heat up because of the heatsinking properties of the copper traces on the board.