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Old 07-03-2008, 07:36 PM   #1
I wanna be Dave
 
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Default Strange Electrical Issue

Well, at least I think it is an electrical issue.

I've got a TC3 with a Reedy 19T, Castle Sidewinder, Associated 27MHz AM Rx, 5955TG, 7 cell Elite 4700 pack and a TQ3.

I can run this car fine, but after about 5 minutes, the power to the motor will cut out and all I am left with is steering. Nothing that I do can fix this problem until I remove and reinstall the motor (leaving the leads connected to the esc). Then, everything works fine again....for another 5 minutes...and repeat.

I have the same problem using my spare esc (Novak XRS) and when I use a different motor (generic 21T).

Any ideas?

Thanks!

Last edited by JeremyH; 07-03-2008 at 07:39 PM.
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Old 07-03-2008, 07:51 PM   #2
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is the voltage cut off set up for lipo?
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Old 07-03-2008, 07:56 PM   #3
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I have no cutoff voltage set.
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Old 07-03-2008, 08:16 PM   #4
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try a different rx i have never had anything but trouble with the AE ones.
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Old 07-03-2008, 08:30 PM   #5
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Ahhh....ok. I have used the same Rx on other builds and hadnt had any problems. I've got an Rx on the way for a scaler build, I'll give it a shot when it gets here.

Thanks for the tip!
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Old 07-03-2008, 09:08 PM   #6
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A few things come to mind, since you still have steering, Rx is probably not it.

5 minutes, while not super long, depending on the gearing and other conditions could be too long.

I would think it is motor or speedo.
1) motor is thermaling and shutting itself down.
2) motor and/or speedo is thermalling and esc is cutting power to the motor.
3) battery is not able to supply sufficient current after 5 minutes and the speedo diverts power to Rx.

More info might help
1) is motor and/or speedo hot
2) do you change battery when you go back out after resetting motor.
3) instead of reinstalling the motor what happens if you just let it sit for 10 minutes.

After rereading your post and noting the reedy 19t I'd suspect motor brushes, as a rule they are only good for about 4 or 5 runs and even then not at full power after 2 or 3. If you running them more than 5 or 6 times there probably shot. 19t TC is murder on motor brushes due to heat. When your removing the motor might you might be disturbing the brushes which would help reseat a hung brush.

Last edited by Miller Tyme; 07-03-2008 at 09:16 PM.
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Old 07-04-2008, 05:09 AM   #7
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Miller Tyme,

your comments are extremely helpful. The motor get's hot, but it is not extremely hot. The XRS will heat up more than I would like, but the Sidewinder does not.

After the short runs, I have hooked up the battery to my Hyperion charger to discharge, and it usually shows plenty of voltage left. I usually do not change the battery between runs, just discharge and charge, then run.

If I let the motor sit, then try to run it again, it will not. This motor is fairly new, but it has about 10 runs on it (using the stock brushes), so I suspect you are right about the brushes. Do you have any suggestions as to a set of brushes that might last a bit longer?

Thanks,

Jeremy
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Old 07-04-2008, 06:22 AM   #8
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Quote:
Originally Posted by JeremyH View Post

If I let the motor sit, then try to run it again, it will not. This motor is fairly new, but it has about 10 runs on it (using the stock brushes), so I suspect you are right about the brushes. Do you have any suggestions as to a set of brushes that might last a bit longer?
I prefer the trinity E brush it is a good mix of run life and performance... but 10 runs is still pushing it. A band-aid fix for worn brushes would be to find a 'comm cleaner' a somewhat abrassive eraser type material and between runs just clean the surface of the brushes and the commutator. It will help remove the carbon glaze from them which is what builds up and causes bad contact between the 2.

Trinity also makes a 'XXX' super high sliver content brush but a $15 it is hardly worth it for anything but serious racing.

Last edited by Miller Tyme; 07-04-2008 at 06:25 AM.
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Old 07-04-2008, 06:45 AM   #9
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OK.

Thanks for the info!
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