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Old 12-07-2011 | 06:48 PM
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Default Limiting kV

Hello.
Im wondering, is there anyway to limit kV on a motor. Well not necessarily on the motor. Maybe on the ESC. I've gotten my self a 3800kV motor and thinking maybe thats a bit much. I also gotten the Castle MMP. Is it possible to do with Castle link?
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Old 12-07-2011 | 07:14 PM
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I think the simplest way would be to limit the throttle EPA on your TX.
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Old 12-07-2011 | 07:18 PM
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Just knock down the pinion size, or go with fewer cells. Also adjust the ESC to provide less timing advance.

Don't use EPA to limit motor performance; the ESC and motor are most efficient running at maximum throttle (at anything less than full throttle, the current ripple cause by the PWMing will cause losses - damn I^2R gets ya every time!).
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Old 12-07-2011 | 07:19 PM
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I have no idea what that means but sounds like he knows what he is talking about so go with that haha.
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Old 12-07-2011 | 07:52 PM
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Hmm I was thinking of stepping down in gears, I though that would lower the torque significantly.
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Old 12-07-2011 | 07:54 PM
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On the ESC you can adjust the throttle curve. Would that help my situation? or should I just save my self a headache and buy a second motor?
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Old 12-07-2011 | 08:03 PM
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Eric: But if you limit your throttle epa on your radio to 90 to 99% from my exprience on my 1/8 e truggy its still pretty efficent and fast . But going less than that it will defietly effect the efficently and power ive tired it before.

100% epa on a dry track at least heck no lol.

Im going to get a castle link field tuner to limit the timing or punch so i can run 100% epa.
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Old 12-07-2011 | 08:18 PM
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What do you guys mean when you guys talk about the efficiency being effected with lower EPA?
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Old 12-07-2011 | 08:25 PM
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Originally Posted by skyrider
What do you guys mean when you guys talk about the efficiency being effected with lower EPA?

Basicly if you lower the throttle epa to much the motor and the esc will have to work harder although with plently of holes in your body for cooling it whouldnt really make it hot . With lower turn kv motors i can see the issue but with a 2200kv motor i run its pretty efficent.
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Old 12-07-2011 | 08:50 PM
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Just use "torque limit" setting in the MMP (using Castlelink)

Effectively lowers the kv

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Old 12-07-2011 | 08:53 PM
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You mean the punch control right? Doesn't that only hold down huge bursts in AMP so it prevents fast acceleration but he would still be able to reach top speed?

Timing and gearing is probably his best option (and controlling his trigger finger too)
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Old 12-07-2011 | 09:13 PM
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No I mean the "torque limit" that has been available on Castle ESC's for a while

Punch control does not change the topend at all, simply changes how throttle is applied

Timing will not help him with a 4 pole motor, all it does is add heat

Agree gearing may be an option if he wants to lower his speed

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Old 12-07-2011 | 09:27 PM
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Isnt that the samething as turning down the expo on your radio or no ?
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Old 12-07-2011 | 11:16 PM
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Nothing like playing with expo or throttle endpoints

Expo simply changes the the throttle response relative to trigger position

Throttle endpoints (travel) changes the ESC's duty cycle

ESC's are more efficient when WOT (wide open throttle) equals 100% duty cycle


The "Torque Limit" setting limits the kv of the motor therefore limits torque

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Old 12-08-2011 | 05:46 AM
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Originally Posted by crusey_aus
Nothing like playing with expo or throttle endpoints

Expo simply changes the the throttle response relative to trigger position

Throttle endpoints (travel) changes the ESC's duty cycle

ESC's are more efficient when WOT (wide open throttle) equals 100% duty cycle


The "Torque Limit" setting limits the kv of the motor therefore limits torque

Cheers




Ok thanks yea there was times when i lowered the expo on my radio to calm down the trigger response especially on a dry/dusty track but now i will mess with the torque limiter.

Them 2200kv motors are torquey man i think its mostly because its sensorless and the kv of the motor also.
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