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Old 06-10-2010, 10:00 PM   #1
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Default what happened to my motor??

Today my Epic Duo2 10.5 was broken after two runs. When it broke, I just heard a big noise, BANG, no smoke, no spark, no strange smell, temp was not even warm, the motor just stopped. I took it off the car immediately, I could not rotate the shaft, when I opened the can, the rotor was broken into pieces (see pics). I don't think my second setup will abuse the motor (first run was cool but lacked top speed). Does anybody know what happened? I think I just lucky enough to get a bad batch

oh, here is my setup
first time
ESC:Tekin RS
boost:40
turbo:10
start rpm:7000
end rpm:12000
FDR:8.0
temp after 6 mins: 135

second time
boost:45
turbo:10
start rpm:7000
end rpm:11000
FDR:8.0

I just put the car on the stand after finishing second setup, then just one single trigger, the motor was broken
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Old 06-10-2010, 10:01 PM   #2
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Quote:
Originally Posted by 05forfun View Post
Today my Epic Duo2 10.5 was broken after two runs. When it broke, I just heard a big noise, BANG, no smoke, no spark, no strange smell, temp was not even warm, the motor just stopped. I took it off the car immediately, I could not rotate the shaft, when I opened the can, the rotor was broken into pieces (see pics). I don't think my second setup will abuse the motor (first run was cool but lacked top speed). Does anybody know what happened? I think I just lucky enough to get a bad batch

oh, here is my setup
first time
ESC:Tekin RS
boost:40
turbo:10
start rpm:7000
end rpm:12000
FDR:8.0
temp after 6 mins: 135

second time
boost:45
turbo:10
start rpm:7000
end rpm:11000
FDR:8.0

I just put the car on the stand after finishing second setup, then just one single trigger, the motor was broken
That's what happens when you free rev motors on the bench.
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Old 06-10-2010, 10:06 PM   #3
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OK, could be, but why it didn't happen when I free reved my car with first setup? I usually free rev a couple of times before I put the car on the track, but nothing happened before, and nothing happened to my other car with LRP X12 10.5
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Old 06-10-2010, 10:08 PM   #4
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I'd say the motor had a bad ball bearing. I had that happen to me once. Was the motor running fine or a little slower when it broke. Free revving does not break your rotors.
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Old 06-10-2010, 10:18 PM   #5
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Originally Posted by M03Racer View Post
I'd say the motor had a bad ball bearing. I had that happen to me once. Was the motor running fine or a little slower when it broke. Free revving does not break your rotors.
The motor was running fine with first setup. With second setup, only one trigger test on the car stand, it just happened in 1 second. Bur before it happened, I can tell the motor ran faster than last last time
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Old 06-11-2010, 12:38 AM   #6
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if you free rev your motor it can easily reach 100,000 RPM. Having a rotor let go like that is a definite possibility. As is stripping your spur gear or any other number of things.
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Old 06-11-2010, 12:46 AM   #7
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your bearing most likely froze up and the rotor was the weaker of two points and snapped under pressure! but ye free reeving your motor is a sin to brushless motors!!! In off road we do it to throw mud off our tires but we are not geared like on road guys either! maybe get away from that tekin stuff and go with lrp just saying! sorry about your luck! that sucks in any case! if your only running 10.5 motor I would suggest going Team ICON Motors fricking awesome and more power to rebuild comes with ceramic bearings as well! they are dialed motors for sure!!!!
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Old 06-11-2010, 07:19 AM   #8
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Your RPM range is way too small. It should be more like 7,000 to 26,000 with a 10.5.

But it was the free revving is what destroyed the rotor. I doubt it had anything to do with a bearing. It only takes one free spool to do it, and it may not happen every time (just because it did it once without exploding doesn't mean you should do it every time).
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Old 06-11-2010, 09:25 AM   #9
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Quote:
Originally Posted by M03Racer View Post
Free revving does not break your rotors.
I guess thats why every motor manufacturer states in their instructions to not free rev the motor?
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Old 06-11-2010, 10:41 AM   #10
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I think the "FREE REVVING" warning is for an UNLOADED motor.
Runnig it on the stand in the car/truck is no more damaging than running on the track.
It's the UNLOADED free rev that blows then up like that.
Bob Oaks
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Old 06-11-2010, 10:49 AM   #11
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Revving a car that is on a stand = unloaded.
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Old 06-11-2010, 10:53 AM   #12
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Quote:
Originally Posted by bob o View Post
I think the "FREE REVVING" warning is for an UNLOADED motor.
Runnig it on the stand in the car/truck is no more damaging than running on the track.

Info Fail. ^^^^

M-Technic is correct.
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Old 06-11-2010, 10:53 AM   #13
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Quote:
Originally Posted by bob o View Post
I think the "FREE REVVING" warning is for an UNLOADED motor.
Runnig it on the stand in the car/truck is no more damaging than running on the track.
It's the UNLOADED free rev that blows then up like that.
Bob Oaks
to much timing free wheeling will do it,the drive train does not add enough drag as much as a 4lb car does on the ground
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Old 06-11-2010, 11:00 AM   #14
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You may be able to salvage the motor by buying a replacement rotor, which is available for about $25 for Duo2 motors.

http://www.teamepiconline.com/shop/i...?item=TRI10305
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Old 06-11-2010, 03:20 PM   #15
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I just got Trinity's reply, they said don't free rev on the bench when the car is loaded, the inertial of tires could blow the rotor up to 40k rpm and the rotor will come unglued. They can offer $20 plus shipping for the rotor, sadly they have to send out insured and signature required, that doubles the regular flat rate. I think I will just use the rotor out of my 17.5 instead of buying a new one
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