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Old 02-10-2005, 05:03 PM   #1
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Motor Break DOES Higher AMP draw = better motor?

I was told that when you break in your motors you can tell what is a good motor vs a bad motor by seeing how many amps it pulls.

I was wondering if this was true or not. If it is what kind of numbers should I be getting as far as amp draw when break the motor in at 2 or 3 volts.

At 3 volts the highest any of my motors have gotten is 9 amp's.

On of the fast guys at my track told me they should be at 12 amps... Is this right???

Most of my motors are pulling around 7-8 amps at 3 volts.

If anyone can help me out with this or what I should be trying let me know.

I am talking about stock motors at this time, but if this relates different to Mod or 19 turn I am interested in that as well.
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Old 02-10-2005, 05:08 PM   #2
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Higher Amp draw doesn't mean it's a great motor. Next time you break in your motor touch one of the shafts and you'll see the amps go up.

Usually a higher amp draw does indicate a better motor, but a dyno or on track performance is the only sure way to tell.
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Old 02-10-2005, 05:17 PM   #3
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or as he mentioned, bad bearings. so more load will pull more amps.
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Old 02-10-2005, 05:21 PM   #4
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From my experience 90% of time a high amp draw motor has always been better than a low amp draw motor. This is providing the motor is in perfect working condition. Also I'm not sure if the same applies for mod motors, I know the theory works for stock motors.
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Old 02-10-2005, 05:29 PM   #5
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in theory yes but there are alot of things to take into consideration.your motor may not be shimmed correctly for instance.this will bind your armature and show high amp draw.the track is the most accurate dyno in my oppinion.doesnt hurt to check them out though.
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Old 02-10-2005, 05:45 PM   #6
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When a motor is new and not broken in it will pull more amps. Once the bushings are no longer bound up the amp draw will come down. So when I'm getting a new motor ready to race I pay careful attention to how many amps the motor is pulling. I work hard at getting the amps down low. After break in I will then worry about tuning the motor for the best RPM and higher amp draw. Keep notes on a particular motor; documenting all runs on the dyno. This should give you a good base line to make changes. Remember, the track is the best place to see how fast a motor is.
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Old 02-10-2005, 05:48 PM   #7
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Quote:
Originally posted by kmorast
When a motor is new and not broken in it will pull more amps. Once the bushings are no longer bound up the amp draw will come down. So when I'm getting a new motor ready to race I pay careful attention to how many amps the motor is pulling. I work hard at getting the amps down low. After break in I will then worry about tuning the motor for the best RPM and higher amp draw. Keep notes on a particular motor; documenting all runs on the dyno. This should give you a good base line to make changes. Remember, the track is the best place to see how fast a motor is.
Kelly, I hope your bushings aren't binding. That wont be a good thing when I come up to Rapid.
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Old 02-10-2005, 09:26 PM   #8
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I'm not an expert (If I touch your motor it loses 5 watts on the dyno), but from what I see of the guys who are fast, higher amp draw is better. The caveat is that they have already reamed the bushings, set the shimming, aligned the hoods, etc. If you just throw your motor on at 3v and go "wow it does 9 amps", it may not mean much. If you have already prepared it, and it is done right, it is a good RELATIVE gauge.
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Old 02-10-2005, 09:40 PM   #9
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Tighten up the brush springs and the amps will instantly go throught the roof. Does this make the motor better? not really.

There is now way to tell which motor will perform better on the track by no load amp draw readings.
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Old 02-10-2005, 09:59 PM   #10
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Cool does that mean if I clamp a pair of vice grips on the motor shaft of my mabuchi motor and it draws enough amps to shut down my T30 it will beat any mod motor on the planet????


Just a bit of sarcasm... this is how I convince guys that the old amp draw test isn't the best way to test your motors..... Unless you are very experienced and know what to look/listen for....
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Old 02-11-2005, 05:51 AM   #11
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I really just use my dyno (not really a dyno more of a motor checker) but anyhow, I use my dyno more for of a way to determain what changes are helping or hindering my motor tuning i.e. if I use a harder or softer spring what changes happen. Mainly I record the RPM which is un loaded but still a pretty accurate for every motor so I know what is working well or not. The Amp draw test is kinda a two edged sword, Unless you know your motor is perfectly built then and only then is the Amp draw revelant other wise it can be a hinderance and hide bad building of the motor.
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Old 02-11-2005, 06:36 AM   #12
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Like others have mentioned, No-load readings mean very little, "everything" can change when a motor is under load .......IMO the motor checkers out there are good for breaking in brushes , and thats about it
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Old 02-11-2005, 08:54 AM   #13
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I've got this 7 single arm that'll pull 20-24 amps at a 1.2V. Motor hardware is in excellent condition: bearings good, no bind, good spacing, etc. The guys say "do it up" but I wonder if it will be a baller motor or if it will turn my speedo into a puddle. Haven't run it since my mangina kinda hurts hehe Any thoughts?
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Old 02-12-2005, 02:02 AM   #14
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Unless theirs something wrong with your speedo , or it has a motor limit....it's should be fine........mod motors pull alot more that that while in the car
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