Burnt' Crawlmaster?

[Mad4Rnr]

So I think I over heated my crawlmaster 3014, it got way too hot to touch and now the coils look dark and discolored. When I first got it it always seemed to stall (kind of like a radio glitch). It would run for a few feet and stall, then run a few more and stall, until it just got way too hot and I'd kill it. I pulled out the crawlmaster and swapped in a 55t integy and it runs like a champ, no stall at all so I'm wondering if I way undersized* the motor and just fried the poor thing or did I get a bad one?
Here is the rig I ran it in: TXT super tuber =

9.8lb custom droop tuber w/TXT axles and R2 trans (8t pinion). 7x 3400mAh knuckle packs, 1400mAh rx pack, XL Moabs...

I was also wondering if a bad solder joint could cause high resistance and fry a brushless? I did recently find I had a bad joint, since fixed.

*Note that at one point I even tried my TLT axles with the crawlmaster and R2 and got the same results.

[JohnRobHolmes]

It very well could have been a bad solder joint. Were the wires all properly insulated from each other? It sounds like you could have gotten a bad motor. It shouldn't act like that at all, and a 10 lb rig really isn't much of a chore for that motor honestly, especially with that geardown.

where was the bad solder joint?

[Mad4Rnr]

The bad solder was at one of the buss bars on the knuckle pack. I took a hard rollover and the shock broke it loose. Like an idiot I used silver solder and I think its kind of brittle. I fixed the one joint but the whole pack is now suspect ( I hope I can resolder the whole pack w/out damage to cells).

When I first put the crawlmaster in my tuber I ran a thunder 6-cell 3400 stick pack and still had the stalling issues.

When I was trouble shooting I was able to run the motor and R2 alone with out issues then when i hooked up the drive shafts the stall started (with either TLT or TXT axles)

Glad to here it should push 10lbs

What about inertia matching? If the inertia of the rig is more than like 10x that of the rotor would it cause it to burn? Is there such thing as intertia matching with sensorless/brushless motors?

[Mad4Rnr]

I wana go back to brushless but I'm worried that if I try another crawlmaster I will fry it again.

Does anyone know if you can resolder sub-c's with 60/40 that have previously been soldered with deans silver solder?

And is there a way to measure the resistance of a battery pack and detect if it has any bad solders?

[EGRESSor]

a bad battery pack will not kill motors
but can kill an esc

some pics of your stator ?

[Mad4Rnr]

OK I may have figured out the burrnt crawlmaster issue. When I first got the truck running I didn't have a chance to program the Mamba Max thru USB to run in brushless mode. Does any one know if the MM can sense which type of motor it has attached to it when doing the initial throttle trigger limit set up? And if I did have it in brushed mode would that fry the 3014?

[xjman]

My MM came in the brushless mode and I had to switch to brushed.

[JohnRobHolmes]

The MM comes in brushless mode.


If there was an issue with the motor construction I will get it replaced pronto. Can you take some pics of it?

[Mad4Rnr]

Originally Posted by EGRESSor

a bad battery pack will not kill motors
but can kill an esc

some pics of your stator ?

Non of the magnets were loose in the rotor and the only visible defect is the overheated coating on the stator coils

Originally Posted by xjman

My MM came in the brushless mode and I had to switch to brushed.

I thought the MM was by default set to brushless mode, I also had to switch it when i put in the 55t, so unless someone messed w/ mine before I got it...

Anyone knowhat the resistance of the coils are supposed to measure? I have a way to measure using the 4-wire method so I can get down to the milli-Ohm range.

[Mad4Rnr]

Originally Posted by johnrobholmes

The MM comes in brushless mode.


If there was an issue with the motor construction I will get it replaced pronto. Can you take some pics of it?

I just ordered another one that should be here tomorrow, first thing I will do test to see if this one acts the same

hey JHR I did notice that there seems to be a little adhesive on the face of one of the magnets and corresponding gouges on the stator core, besides the detent torque it rotates freely though

[JohnRobHolmes]

Originally Posted by Mad4Rnr

hey JHR I did notice that there seems to be a little adhesive on the face of one of the magnets and corresponding gouges on the stator core, besides the detent torque it rotates freely though

Did the can ever take a hit? That is generally the cause, and the stator gap is so tiny on these motors that even large falls could make it scrape if it is rotating. As long as it rotates freely you are just fine, the stator plates and magnets are not effected by surface scratching.

The next batch of motors will be sealed more, to prevent foreign debris from entering just in case. I know they wont overheat.

[EGRESSor]

for measurement
you can run the motor with a drill machine at constant rpm
need to measure the voltage between any 2 motor wires 1-2 and 2-3 and 1-3
must be the same voltage

[Mad4Rnr]

All three coils measured approx. 1 V rms at 1250rpm. The coils were evenly matched so I wonder if I just stressed motor by running too much current thru it. I do have a 10lb rig with a 7cell 3600mAh pack and had the MM set to full power forward/reverse, full drag. I thought I tried running the MM at 70/30 with same stalling issues, I just hope I don't burn the one showing up tomarrow. Maybe I'll just put the new one in my TLT with a Mamba 25. :-(

[JohnRobHolmes]

That really shouldn't have been an issue. I say run the new one as you did the old one, and keep an eye on the temp.


Just make sure your vehicle rolls freely when no motor is installed.

[Mad4Rnr]

Got my new Crawlmaster today and I'm having the exact same problems as previously. When I run it up slowly through the RPM rangle its OK until it gets to about 75% throttle and then it stalls out, same thing in reverse. Motor gets hot super fast when run and stalled but not in neutral. I messed with the EPA's again as well as all* the MM settings, nothing worked. The drive train turns smoothlyand I even tryed messing with the pinion to get more and less backlash. Here is a vid of the symptom:



*actaully not true, I have yet to mess with the timing settings

[JohnRobHolmes]

You need to reprogram your throttle endpoints on the mamba max if you have not already done so.

[Mad4Rnr]

Originally Posted by johnrobholmes

You need to reprogram your throttle endpoints on the mamba max if you have not already done so.

I tried changing the endpoint in my futaba 3PM radio and had to set them at 40% to get the glitch out and then it had no power and wheel speed.

I don't know how to set the end point in the castle creations software. I assume it has someting to do with the throttle curve tab and adding the blue dots to tweak the curve. I will experiment more....Thanksman

[JohnRobHolmes]

That is not what I am talking about. Do you have your manual for the mamba max?

pg. one, quick start guide. Follow that.

[Mad4Rnr]

Originally Posted by johnrobholmes

That is not what I am talking about. Do you have your manual for the mamba max?

pg. one, quick start guide. Follow that.

I did the initial set up again and it still stalls, i ran it around the garadge a bit and noticed it seems to stall under heavy load at low speeds and at no load it stalls near max throttle.

I might try a GD600 but i was hoping to not have too

I know Ive seen other guys run 770kV motors on TXT trannys before, I feel defeated by the brushless

[EGRESSor]

TXT super tuber =
do you have changed the mode after the lathe motor ?
i would test it with the mamba 25 instead of the MM