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Feb 26, 2020, 12:54 AM
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Discussion

am i killing my motor?


Hey all, i have an arrma infraction, use it primarily for speed runs. I have a castle creations 2200 kv motor with a mamba monster x 8s, the motor is rated for 6s my max rpm is 60,000 on 6s, but on 8s its 65,120. Ive looked at my logs and ive seen voltage go to 30.4 volts, 78 amps. Im running a 27 pinion 46 spur. Do i need to get a motor rated for 8s? 6s is what its originally rated for. But 8s is so much more fun. 6s is fun too.
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Feb 26, 2020, 01:36 AM
If it flies, I can crash it.
rocketsled666's Avatar
So that's about 2400W, or almost 2 HP. Which is why it's fun, of course.

You need to go look up the specs for your motor. It should have a max Volts, Amps, and Watts specification. Ignore the Volts spec. If your 78 Amps is less than the motor's max, and your 2400W is less than the motor's max, you should be all set. If either is over the corresponding motor spec, then yes, you're killing your motor.

The primary issue is heat, which can burn winding insulation and cause magnets to demagnetize. If the motor temp after a run is north of maybe 120C you're probably too hot regardless of what the motor's specs say. Lick your finger and touch the motor casing. If it sizzles, that's bad.

These rules apply to anything with an electric motor, car, boat, plane, quad, heli, etc.. It's mostly just about how hot the motor gets in operation and less about Amps and Volts.
Feb 26, 2020, 09:25 PM
Wake up, feel pulse, be happy!
Piece's Avatar
2400W = 3.2 horsepower.

You CANNOT just "ignore" the motor's voltage rating in this case. Spinning it too fast will turn the rotor to shrapnel. It doesn't usually matter in direct-drive plane and quad motors with nonsense Chinese specs, but in a geared application where the manufacturer's voltage rating is based on max safe RPM, you need to adhere to that rating.
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Feb 26, 2020, 09:28 PM
If it flies, I can crash it.
rocketsled666's Avatar
You mean 2400 divided by about 745 doesn't equal 2?

Yeah, I must have been on glue last night. Not that I remember of course.
Feb 27, 2020, 08:32 AM
Did I make the A Main?
bill_delong's Avatar
what are your temp readings?

PRIMER: What gearing for upgraded electronics?
Feb 28, 2020, 12:13 AM
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Temps are around 160 170
Feb 28, 2020, 12:14 AM
If it flies, I can crash it.
rocketsled666's Avatar
Centigrade? That's way too hot. Farenheit? Those temps are absolutely fine.
Feb 28, 2020, 12:39 AM
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https://imgur.com/oLmkUkH
Feb 28, 2020, 12:41 AM
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a pic should be uploaded shortly of the data log
Feb 28, 2020, 02:22 AM
If it flies, I can crash it.
rocketsled666's Avatar
Those temps are absolutely fine. In fact, you could push this motor harder and probably still be OK. 100F is nothing. 100C is where you need to start worrying.
Feb 28, 2020, 09:29 AM
Did I make the A Main?
bill_delong's Avatar
His motor temp reading was 169F toward the end of the run, that is a pinch higher than I am comfortable recommending... I would consider installing a cooling fan on the motor if it were me. This will become very important in the summer when ambient temps go up, so will your motor temps
Feb 28, 2020, 10:13 AM
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I ordered a cooling fan from amazon the hot racing dual ones


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