Ezrun overheating?

[Ian_Gsi16V 533]

I have started experiencing overheating issues with my blitzer beetle and was wondering if any of you guys can point me in the direction of a fix...

Spec:

EZRun 35a ESC 9T Motor
13T Steel Pinion.
2S LiPO 30C 
Extension leads connecting ESC to Motor

System is about a month old and has probably had about 12 packs run through it, used to barely break a sweat but about a week ago I hit the beach, didn't relalise how open the motor really is and it got filled with sand, I stripped it and cleaned it up and it seemed ok but it seemed to be getting hotter than usual but ran fine. 

This weekend just gone I was using it, worked fine but again motor was getting very very hot, I picked the car up by the rear end and dropped it as I scolded my finger on the motor so obviously not right. Gearbox and all running gear is fine and not binding as I stripped it all down last week so it is nice and smooth.

Now after about 10 minutes of running it starts cogging and I have to turn it off to cool down, the ESC isn't hot though so is the thermal shut off relevant to the ESC or the motor?

I have purchased some wire so I can remove the extension cables but have I killed the motor when I got it full of sand? I spins freely and doesn't appear to have any binding but I can't inspect the state of the coil inside. I have actually purchased a new motor as I stumbled across a replacement for £10 so seemed a worthwhile investment but I have a desire to know what went / is going wrong. 

Thanks. 

 

 

[Darat76 265]

run a silver can for a few packs, if the problem remains you do have a binding issue, if not your going to low in the turn count for the gearing, with the wheel and tyre combo.

I'm assuming that's a brushed combo, so in your shoes, I'd go buy a brushless combo around the 3500kv mark, soon I'll be able to let you know how a reedy sonic mach 2 9.5t goes in this chassis.... as soon as it arrives.... and i get to solder it up...

[Ian_Gsi16V 533]

Hi, 

The EZRun is a brushless system. I had another look at it last night, my replacement motor spins very smoothly when throttle is applied (as expected) but when I tried my current EZRun motor it does appear to have a little resistance which I couldn't really pick up on until I had another brushless motor to compare it to, plus it was smoking when I tested it which I am going to assume is not a good sign 

I think it is a fair assumption to assume it is dead, for the price of a replacement I might as well just chuck it. 

[Darat76 265]

Catch is, had you run that motor before you stripped, cleaned, and repaired the gear box? or was it a new one after you had done that?

[Ian_Gsi16V 533]

Yes, I had run it after I rebuilt the gearbox and it seemed fine, I got a good 25 minutes out of it although it did seem hotter than it should have been.

One of the main things that impressed me when I converted to brushless was how low the motor temperatures where.

[Darat76 265]

so that now goes back to gearing, wheel size, and more damage to the gearbox.

as annoying as it is, open up the gear box and make sure nothing is damaged, actually, if the motor is still in, sit the car on the ground, turn into the 6 yr old in all of us (motor sounds optional) and push it around by hand some, both forwards and back wards, then do the normal thing we did at that age and make it "fly" like a space ship/plane (can just vaguely remember doing that as a kid with my matchbox cars). if something tightens up, or something rattles and clatters (other than plugs) then that is where your problem is. otherwise, open up that gear box and double check all is still good in there.

gear box sorted? and all good? ok give the front wheels a spin, make sure they spin freely, that wobble you see is just the wheel balance, don't worry, there is no feed back to the steering wheel, so it won't try to jump out of your hands, just tell your car's driver your sorry, but balancing the front wheels costs to much on his ride and he'll just have to put up with that vibration for longer, tho if you leave it for long enough he may just fall to pieces on you...

lastly is the motor, yes it may have been dodgy, but also yes, that gearing may be to much for that motor. are you sure it is a true 540 can brushless motor, or is it a 380 motor with an enlarged to match can. cheap motors are cheap products, and as we all know cheap = short life span, hunt down your local rc racing club, go down and meet the off road members, find their web site, and stalk the top racers, they will regularly update their gear, which is a good way to get race quality gear that has been looked after nice and cheap, not just motors, but esc's, servo's, and even radio gear, and even cars, complete, rollers, or bare bones.

[Backlash 481]

How are the bearings in the motor??

Could one (or both) be seized??

[Ian_Gsi16V 533]

2 hours ago, Backlash said:

How are the bearings in the motor??

Could one (or both) be seized??

Both bearing seem 'OK'. I would certainly say the sand hasn't helped but I cleaned them out and they spin freely. 

If I get time later I will take a quick video of the motor running out of the car.

 

[Darat76 265]

with bearings, hold them and slowly turn them by hand back and forth, if they feel notchy it means there are flat spots and ridges from corrosion and they should be replaced, even tho it feels minor to you, it is quite a bit of resistance for the motor to over come on each bearing that is in that state. A good bearing will spin so smoothly you won't feel the machining marks on the balls or the races.

[Ian_Gsi16V 533]

Just to update this at where I am now..

Installed my replacement motor (Turnigy 9T Sensorless Brushless) in place of the EZrun 9T.

Ran a couple of a batteries through it already and it is now performing as normal, very little heat generated from the motor (even after 25 minutes, I can comfortably touch and hold my hand on the motor) and no cutting out so I would conclude that my EZrun motor was as suspected, ruined by sand!  

Now to make this one completely sand proof