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Daves956

Brushless motor overheating questions

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I've got this 5700 KV castle brushless motor that gets way too hot. I'm not the original owner so I don't know it's history but it was noted by the last owner that he noticed it too and never really ran it much. It doesn't seem to matter what voltage or pinion it's running and will get hot pretty quick completely out of the car.

I had it in a stadium truck and in 20 minutes with the smallest pinion I could use it got to 250 degrees. I know this is way over anything recommended but I have to ask.

At that temperature was this one permanently damaged? I see it can be opened up but is it worthwhile to even try to maybe fix it? If I do open it up is there something to look for as far as it being repairable or not?

Thanks

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Over temperature will do two things. Melt the glue that bonds the magnets together and to the shaft (delaminate). Cause the magnets to loose their magnetism.

You should always adjust the Castle software in the ESC to lowest motor timing advance. This is the biggest heat generating setting.

A 'stuttering' motor will heat up very quickly. Which is one that is either not receiving a clear phase signal (ESC problem), or is itself not using that phase signal correctly due to a break in a wire or a poor connection.

There's not much in the motor that you can fix. Replace the bearings if they are worn is about it. Note that the end is not just bolted on, but it's also bonded (glued) on there pretty securely too.

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It sounds like I'm the proud owner of a paper weight. It's not a big deal since I have a replacement for it but figured I'd ask before I give up on it.

Thanks

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For some motors you can order and replace only the rotor, not sure if it's worth the try, the windings may also be damaged

Probably better to get an identical new motor and keep this one for parts

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The CM36 series of 2 pole motors have been discontinued for some time. All now replaced with the 1406 series of 4 pole motors. 4600Kv, 5700Kv, 6900Kv and 7700Kv.

The 3800Kv 4 pole motor is the best Kv of their range for tamiya models with limited gearing options, but it is slightly longer in the motor can being a 1410 series motor so may not fit in some chassis.

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I've got 2 of the fuse 5800 kv 2 pole motors without ESCs right now so I'll try pairing one of those. It was too much for the stadium truck anyway and I already put a 3500 KV reaktor in it.

I picked up a Duratrax/ Castle 4 pole 3900 yesterday just in case.

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Farenheit

So about 120 in modern terms. Yes, that's a bit too high (but not as bad as I thought!). I've had a motor up above 110c without any long term damage, but I would think that consistent temps in that range would be bad. As above, there not too much you can do, a visual inspection, clean and perhaps check the timing.

If it was 250c I was going to advise you that it's dead... :D

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It about burnt my hand when I picked it up, so since this was meant to go into a stadium truck for my daughter it won't get used.

I got both the motor and ESC used with the warning about the motor possibly having a heat issue. The price was well under the new cost for a ESC or motor and it now seems to be ok with the fuse motor. Right now I'll put the combo away for use in something else but it's good to know the limits and results from that kind of heat.

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Castle recommend nothing over 200F, but I always try to keep mine around 160F (~70C). That's still hot enough that you can't really touch it and the only way to be sure of the actual temp is a thermal probe (temp gun).

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That's just to high KV motor for what your cars gear ratio... in fact if you over heat your motor it gets ruined and it will then heat up more and more because you toasted it the first time around... guy's stay under 150 Deg 140 a hair over is my target anything over deteriorates the rotors magnet and then you get the hot running motor syndrome and weaker motor.

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Unfortunately, I think this one was overheated before I ever saw it. I guess that's a kind of hidden problem with a used motor but at least the guy I got it from discounted it quite a bit and warned me about it maybe being an issue.

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Most times the motors have anodizing on the aluminum motor cans and you can tell if they where over heated as the color won't be dark it will look washed out and faded a little.

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Most times the motors have anodizing on the aluminum motor cans and you can tell if they where over heated as the color won't be dark it will look washed out and faded a little.

Thanks for the tip on that. This is the first green Castle motor here but it does look like it's been hit with dull coat. The other thing I've noticed with it is that you can't feel the magnets as you turn the motor by hand. All the other brushless I have here give some resistance when you turn the shaft. This one has none.

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Thanks for the tip on that. This is the first green Castle motor here but it does look like it's been hit with dull coat. The other thing I've noticed with it is that you can't feel the magnets as you turn the motor by hand. All the other brushless I have here give some resistance when you turn the shaft. This one has none.

Probably toasted from what you described.

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