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View Full Version : Does MR03 have some sort of overload/thermal cutoff?


greenepa76
2010.12.07, 10:16 PM
I was wondering if anyone knew or have had this happen. I burnt out two FETs and ended up replacing all of them recently and can't explain why the car completely cuts off after several laps of on/off throttle driving around the track. I'm using a PN 50 turn motor and have it geared within spec, but on the higher end of the recommended limit. The motor nor the plastic around the FETs seem to get hot at all. Just a little warm and not anywhere near the hot temps the stock Kyosho motor would run.

Is this just a built in overload shutdown on the board? The car runs perfectly fine and pulls strong, but cuts off for a minute and then resumes. If I try to run before it resets, it moves at a snail's pace and then completely cuts off til I wait for it to "reset". Afterwards, it runs normally again til it cuts out and repeats itself.

Anyone recognize what these symptoms are?

Thanks!

Action B
2010.12.07, 11:24 PM
I was wondering if anyone knew or have had this happen. I burnt out two FETs and ended up replacing all of them recently and can't explain why the car completely cuts off after several laps of on/off throttle driving around the track. I'm using a PN 50 turn motor and have it geared within spec, but on the higher end of the recommended limit. The motor nor the plastic around the FETs seem to get hot at all. Just a little warm and not anywhere near the hot temps the stock Kyosho motor would run.

Is this just a built in overload shutdown on the board? The car runs perfectly fine and pulls strong, but cuts off for a minute and then resumes. If I try to run before it resets, it moves at a snail's pace and then completely cuts off til I wait for it to "reset". Afterwards, it runs normally again til it cuts out and repeats itself.

Anyone recognize what these symptoms are?

Thanks!

When it "cuts off" does the power light stay on?

greenepa76
2010.12.08, 01:25 AM
Everything is on and functional except for throttle. If it sits long enough and you depress the trigger before a full reset, the throttle barely moves the motor. As you wait a few more seconds, and do the same thing, the throttle will come back slowly. Waiting and never touching the throttle trigger and about a minute is the only way it will return to 100%. After a few laps of loading up the motor, the throttle cuts out completely again, but steering and lights are all on.

Felix2010
2010.12.08, 02:01 AM
I've had this happen to me on my 03(s). I run super-hot proprietary motors all the time and I run 2x3 Fet stacks on my cars (or I run Nelly turbos = 2x5+ Fet stack) and sometimes the car's throttle will just go "Off" completely. Steering stills works and everything just like you said grenepa76.... Sometimes the Fet's and motor are a little warm though, so I thought, like you, that the 03 electronics RA-22 PCB unit might have some logic circuit on it to prevent blowout.... I have yet to find the cause or a solution to the problem. I usually have to leave the car off for 5 minutes, or I need to take out all the batteries, re-install the batteries (same ones), and then power back on. Then usually everything goes back to normal.
Weird problem...

greenepa76
2010.12.08, 11:10 AM
Thanks for the input Felix2010. Strange, PN racing says that their motor should work with stock FETs and the recommended gear range, which I am in spec. But I've upgraded the FETs and still within gear range and it cuts out. Maybe I should just drop it off at Kenon so Philip can take a look at it.

lfisminiz
2010.12.08, 07:36 PM
Maybe a fett problem? Have Philip look at it.

Gadgetguy
2010.12.10, 03:55 PM
As per the users guide this is normal. In case of overheating the car will stop.

A few minutes later it will start again.

Skv012a
2010.12.10, 05:14 PM
Time to add heatsinks on our Zs eh?