Kraton Chasing sudden heat issue

Vanning

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All of a sudden my Kraton has been running hot...It will get way too hot within a few minutes. Normally it runs in the 130-150 range at the end of a full pack. Now it shoots way up to 170 plus fast. I've slowly been looking it over and I'm in the process of soldering some new connectors on. The reason for that is because that's about when it started running hot. (I got new Castle connectors right before the heat issues) While I'm waiting for fresh XT90 connectors to come in the mail, I decide to try and look at the motor to see if I can find anything wrong. This is a pretty neat test that could give a good indication if the motor is starting to go.
Put the motor shaft into an electric drill, and spin the motor at the drill's top speed. (secure the motor can so it does not turn) You can then measure the back EMF AC voltage from A-B, B-C, and A-C (the 3 wires) while the drill is spinning the motor. All three AC voltages should be the same if the windings are in good condition. The amplitude of the 3 voltage readings will depend on the Kv of the motor and the speed that the drill is turning the motor.

Mine checked out ok on that test but it's pretty neat that these motors are like old motorcycle generators. I also checked resistance between A-B, B-C and A-C, that was all low and the same. Checked the bearings etc also. All that seems ok.

Hopefully it's just a bad solder on one of my connectors. I'm not really a fan of the Castle Connectors...That's why I just ordered new XT90's. Going back to old faithful...they solder up way easier. I tried the big Green Castles....I don't think I'll get them again. PITA to remove if you have to.
 
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dpricenator

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That is a cool trick with the motor. I just got my temp gun so I'll be taking some temps during the next bash.
 

Vanning

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I use one every run but mostly after changes are made. I looked for one to hook up into the vehicle. Venom had one out but now it's hard to find.
 
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Kauaiguy

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I use one every run but mostly after changes are made. I looked for one to hook up into the vehicle. Venom had one out but now it's hard to find.
Theres those heat stickers that change color,you just have to buy the one that is close to the target temp,though about doing it myself but keep using the heatgun.
 

ParkRacing

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All of a sudden my Kraton has been running hot...It will get way too hot within a few minutes. Normally it runs in the 130-150 range at the end of a full pack. Now it shoots way up to 170 plus fast. I've slowly been looking it over and I'm in the process of soldering some new connectors on. The reason for that is because that's about when it started running hot. (I got new Castle connectors right before the heat issues) While I'm waiting for fresh XT90 connectors to come in the mail, I decide to try and look at the motor to see if I can find anything wrong. This is a pretty neat test that could give a good indication if the motor is starting to go.
Put the motor shaft into an electric drill, and spin the motor at the drill's top speed. (secure the motor can so it does not turn) You can then measure the back EMF AC voltage from A-B, B-C, and A-C (the 3 wires) while the drill is spinning the motor. All three AC voltages should be the same if the windings are in good condition. The amplitude of the 3 voltage readings will depend on the Kv of the motor and the speed that the drill is turning the motor.

Mine checked out ok on that test but it's pretty neat that these motors are like old motorcycle generators. I also checked resistance between A-B, B-C and A-C, that was all low and the same. Checked the bearings etc also. All that seems ok.

Hopefully it's just a bad solder on one of my connectors. I'm not really a fan of the Castle Connectors...That's why I just ordered new XT90's. Going back to old faithful...they solder up way easier. I tried the big Green Castles....I don't think I'll get them again. PITA to remove if you have to.
That sucks, I hope it is something simple and not the motor, no reason it should go since you take good care of your equipment. I went with the Castle connectors when I saw you were using them, sorry to hear you don't like them.
 

Vanning

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Well... right when I changed the motor mount, connectors and the battery, I started with heat issues. I gradually started to notice with the newest parts, and now it's just obvious something is off. It could be a bad connector because I got some cogging but very brief. Don't get me wrong, the castle connectors are real nice but it seems hard to unsolder them. I think I may have screwed up a solder joint. It seems to hard to fix it now so that's what I don't like. If it was a XT90.... it would be easy. So you know me.... I'll be the first to complain about something and report it to fellow Kraton enthusiasts. So I just decided to go back to an XT90 to see what happens. It appears that the motor is working fine per several bench tests. The HR motor mount wasn't causing it.... last thing is to check the connectors.... or maybe I'm loosing a phase on the ESC ??? Idk yet but it's getting nice out... just want to check the obvious and hope it's just simple. I got the entire thing done up nice and now have to deal with an issue. Plus.... I had to go and snap a new shock also first few off road runs of my rebuild. What I really should do is check the motor connectors also, could be intermittent in those wires.
 
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Vanning

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IMG_0766.JPG
Back in business !!!! Removed the Castle 6.5mm connectors, added back some fresh XT-90's. I'm not sure what was up but that was the first time ever that I had battery to ESC connectors cause me issues. It was probably solder related but they sure looked ok....????
 

Kauaiguy

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Don't feel bad,had the same experience with my Leo 4082,changed to the 4092 still had heat problems,changed the esc and was good so i resoldered my battery wires on the "bad" esc and it to ran cooler.When resoldering i did see that only the outside was melted,core was not hot enough.These things suck some amps,so a bad solder joint will show at some point!
 

Vanning

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Another thing to watch out for....Lots of these wires are tinned from some factory some place. They probably use some sort of inferior solder with no lead or flux in it. If you do not snip it off, you will just solder it into your quality solder that melts much easier than the cheap stuff. So now you got a hunk of cold solder under your good quality stuff because that stuff melts at a higher temp than what you are using.

I'm starting to wonder if that's the reason my old Leo was running at nuke temps ? I had a different wire harness on it. When I got my new Leo....I made a new harness from all new heavy wire etc. I made sure every joint was clean, then liquefied the solder and set the joint nice. Wow...very sensitive when you get up to high amps.

Now...what I was saying with the big green Castle connectors. I really could not get them apart to try and redo them. I didn't want to snip the wire etc. At least with a XT-90, you can work on them much easier and really see what you are doing. With the Castle, it seems like a one shot deal. Once you jam the bullet connector in the case, I don't think it will come out too easy.

I tried them, they are good but I rather see a tab that sticks out like an XT-90.

One other thing.......God does this thing rip !!!!! Love this setup, weather is trying to break, it's time to run this stuff.
 
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Dustin Mustangs

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Butane pencil torches work great for connectors too big for your iron. Just be careful you don't melt the insulation.

6-1326.jpg
 

Monsterbrad

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I have to add....
Don't forget to check your drive line.
PINION bearings can cause the heat issue as well.
Also check for binding on all rotating areas.
 

Vanning

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I have to add....
Don't forget to check your drive line.
PINION bearings can cause the heat issue as well.
Also check for binding on all rotating areas.

I know... that is a huge thing to check. I recently changed out one bearing in one of my RC's that was going bad. This bearing is hard to see and also hard to get to. It's also not obvious when it starts to go. What it causes is bad gear mesh with the spur and pinion. What a world of difference after I replaced it.
 
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