Weird problem with motor or esc

[jeff22]

I have started to notice that my motor and esc have been getting much hotter than normal. I also started noticing that the truck is much harder to push with no battery connected than it used to be. I used to be able to push it very easily when it was off.

Now though it is very hard to push, the tires starting sliding on the bench surface before it starts moving the drive train.

I took the motor out to check drive train binding and everything is smooth. I put the motor back in and checked the mesh and everything is good and still smooth.

Here is the weird part as soon as i wire the motor to the esc it gets very hard to push, if i disconnect one of the motor wires it goes back to being easy to push. There is no battery in the truck when i'm doing this.

Would this cause the esc to get hot? Is it more likely the esc or the motor causing the problem?

When I hook up a battery and turn the truck on the pushing resistance is about half way between when it's off with motor hooked up and off without the motor hooked up.

I'm pretty sure it wasn't like this before, I remember being able to push it around on the bench easier than it is now when the truck is just sitting there.

Here is a video showing the problem, All i'm doing is connecting and disconnecting the power wire from the esc to the motor with no battery installed in the truck. When the motor is connected to the esc the truck becomes very hard to push.

https://youtu.be/XXoQCL0lLls

[new2rocks]

Looks like your motor may be fried. Have you tried running the motor disconnected from the tranny to see what happens? If it gets hot quickly with no load, it's time to replace.

[robertjpjr]

You probably fried the brushes in the motor. Cheap axial 27 turn by the looks of it. Get yourself a nice rebuildable or honestly, I've had nice luck with Traxxas 21t 550 motors.

[TacoCrawler]

Power on with a drag brake esc will limit neutral/coast.
^ assuming your esc is drag brake capable/set.

But yeah...
an excessively hot motor could be a sign of motor wind/brush failure soon approaching.

or

Excessive motor/esc heat is often generated by excessively tall gearing...
What pinion/spur combo are you running ? Motor wind ?

I like the cheapo Axial closed endbell motors...
dependable, cheap to purchase/abuse/throw away when their toast.

[jeff22]

The truck is a stock trail honcho with stock motor and gearing I think it's a 20 tooth pinion and 87 tooth spur. It currently has BFG Krawler tires that I got from a Jeep CR edition. These are taller than stock so I put the stock tires back on it and tried running it again with no change (ESC still gets hot).

The ESC is getting the hottest the motor gets warm. I don't know the ESC temp but it is uncomfortable to touch for longer than 5seconds. Before after running in similar conditions the ESC would hardly ever even get warm now it gets hot.

I guess I'll try changing the motor it's only $15 and see what happens.

[jeff22]

After doing some more reading and searching I came across an answer from someone who had this same issue and emailed castle creations about it.

The reply was: "This is completely normal. It takes a long time for the capacitors to discharge when you unplug them during which time the ESC brakes the motor. If this did not occur you would have a problem in that the capacitors would have to be damaged for the motor to turn easily when the ESC is unplugged."

I have confirmed this. I just tried to move the truck after it has been sitting all day and it moved freely like it always has. I plugged the battery in and turned it on then back off again and it was difficult to push again.

So this is all normal operation. Maybe the ESC getting hot is normal too as I can't find any explanation and don't have a reliable way to check the temperature.

I guess it's time to buy a IR thermometer.

[MaFoDes]

Huh... Never heard of it. But who am i......
Something new learned today. I do not have this with any of my cars. Interesting!

[Eric0424]

Originally Posted by jeff22

The reply was: "This is completely normal. It takes a long time for the capacitors to discharge when you unplug them during which time the ESC brakes the motor. If this did not occur you would have a problem in that the capacitors would have to be damaged for the motor to turn easily when the ESC is unplugged."

Must be a Castle thing, it doesn't happen with Novak and didn't notice it with the RX8 Gen2 or LRP ESC's either.