Motor glitching in reverse and overheating.

[skkeeter]

I'm having a few issues with my Losi Comp crawler after putting it together and running it for the first time. I got it used of Ebay, but in really good shape. I ran it for around 15 minutes and the motor was too hot to touch for more than 5 seconds. The ESC didn't feel hot at all. When I'm on a steep incline and want to reverse the crawler at ultra slow speeds, it glitches down instead of running smoothly. Forward has similar issues, but not as bad. The throttle trim is neutral and seems fine. While on flat ground, the crawler doesn't have these issues, only under a load does it happen. Pinion and gear mesh are correct and the crawler tranny runs smoothly. In every other aspect, the crawler runs great. Any advice on the glitching and hot motor?

Here's what I'm running:

Used Losi Comp Crawler
Novak Goat Crawler Brushless ESC/Crawler Brushless Motor Combo (18.5T)
14T pinion
7.4 volt Lipo Losi pack
Does not have a BEC installed. I bought this, but haven't installed it yet. Will it help? http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXSGC1

Thanks in advance, Skkeeter

[EddieO]

Sounds like you need a BEC is my guess......try installing it and see if that helps the problem.

Later EddieO

[EeePee]

Is the drag brake in the controller turned off? What mode are you in?

Servo/Robotic Mode — features precise and symmetric motor control in forward and reverse for robot applications, but without the drag brake. This mode is also ideal for use in a Losi® Comp Crawler™ ...

http://www.teamnovak.com/products/es...oat/index.html

[indiana mudcat]

Could be the sensor harness also, doesn't take much more than a tug to turn the silver Novhacks into glitching paper weights. Myself and several other locals have had issue's where the truck would drive on flat ground but go crazy under a light load, I've had the motor shoot to over 180 just seconds after being plugged in with a bad sensor harness also.

[skkeeter]

Originally Posted by EeePee

Is the drag brake in the controller turned off? What mode are you in?



http://www.teamnovak.com/products/es...oat/index.html

Good advice, thank you very much. I believe it's in the default mode so this will probably help even if it's not the problem!!

Originally Posted by indiana mudcat

Could be the sensor harness also, doesn't take much more than a tug to turn the silver Novhacks into glitching paper weights. Myself and several other locals have had issue's where the truck would drive on flat ground but go crazy under a light load, I've had the motor shoot to over 180 just seconds after being plugged in with a bad sensor harness also.

I'll definitely check this as well. What could the overheating issue be?

[indiana mudcat]

Something about when a harness goes bad can cause a huge amp draw, when I had a wire broke and the motor shot to 180 the battery and deans plug were also very warm. If your on the default profile though the drag break creates heat that you don't need also. Another thing it could be and EeePee will have to confirm this, if it's a ballistic motor it could be the feel of the 14mm rotor.

[EeePee]

I was guessing he has the original crawler stuff.

Another question might be when was the last time you greased it?

And do you have the right gears in the axles... ?

[skkeeter]

Originally Posted by indiana mudcat

Something about when a harness goes bad can cause a huge amp draw, when I had a wire broke and the motor shot to 180 the battery and deans plug were also very warm. If your on the default profile though the drag break creates heat that you don't need also. Another thing it could be and EeePee will have to confirm this, if it's a ballistic motor it could be the feel of the 14mm rotor.

I just ordered a new Novak 6" harness from Ckrccrawlers. So It might be normal for the Ballistic motor to run hot? Could it be time for a motor fan? I love this forum, so much help when you need it. Thanks guys!!!!

[benoj]

the ballistics dont run any hotter than the others but if it was ballistic crawler motor it would have the larger 14mm rotor which could cause a bit of what looks like glitching at low rpms

[skkeeter]

Originally Posted by benoj

the ballistics dont run any hotter than the others but if it was ballistic crawler motor it would have the larger 14mm rotor which could cause a bit of what looks like glitching at low rpms

It's not the Ballistic motor, it's this one,
http://www.amainhobbies.com/product_...ess-Motor-185T

i installed the BEC this morning and reprogrammed the ESC to mode 3 for the LCC. All my issues are still the same and the motor is still really, really hot after 5-10 minutes of running time. Glitching might be the wrong word to describe the problem. It's more of a really slow stop and go hesitation when reversing at ultra low speed backwards downhill. Forward is fine. Actually on flat ground if I start the crawler forward at the lowest possible speed and it encounters an obstacle, there is the slightest hesitation and more throttle is required. This is probably normal.

On another note, I have the Goat 3s 21.5T Ballistic esc/motor combo in my other LCC without any of these problems, which is why I think something is wrong. Especially the heat issue. My Ballistic 21.5t runs way, way cooler.

[EeePee]

Proper gear set in the axles? Gear mesh correct? Again, greased?

[skkeeter]

Originally Posted by EeePee

Proper gear set in the axles? Gear mesh correct? Again, greased?

This is exactly what I'm doing next. I'm going to disassemble the axles and check them out. How do I check the proper gear set? The losi Comp is #001208. Is this one of the older one where the axles need things removed and updated? I did buy it used.

[indiana mudcat]

You won't be able to change the harness on that motor, that's what make em paperweights when the harness goes bad. Hopefully it's in the gears or tranny, can you swap your other motor or motor/ESC combo in to see if the problem goes away?

[skkeeter]

Originally Posted by indiana mudcat

You won't be able to change the harness on that motor, that's what make em paperweights when the harness goes bad. Hopefully it's in the gears or tranny, can you swap your other motor or motor/ESC combo in to see if the problem goes away?

That will be my last resort, but a good idea. i just pulled apart the rear axle, and instead of extra shims(A635, mine has none. Is that bad? Too much play? Sorry if this is getting off topic from electronics.

[skkeeter]

My bad guys, Newb mistake. When I was looking for the extra shims, I looked on the worm gear only. The shims were stuck to the bearing. It had 2 shims all around, so I removed one off each axle. I'm hoping this will solve the problem. Thanks again


Update. After removing the extra shims and re-greasing the worm drives, the initial 10 minute test run has been a success. It is beyond me how much of a difference it is after removing 4 little washers. Go figure. No more hesitations and the motor is running cooler so far. I also tightened up the slipper which could have made a difference as well.