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Old 04-13-2007, 03:42 PM   #1
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Default Amp Draw

Going through my box of motors now that i have a pulsar, wondering what are good numbers at 2v?

CO27 #1 - 7.1 Amps
CO27 #2 - 5.9 Amps
Monster #1 - 6.6 Amps
Monster #2 - 7.6 Amps
Monster #3 - 8.1 Amps
Monster #4 - 7.1 Amps

Ultra Bird #1 - 9.2 Amps
Ultra Bird #2 - 8.9 Amps
Ultra Bird #3 - 8.2 Amps
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Old 04-13-2007, 04:15 PM   #2
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Generally the higher the amp draw the better but this can be effected by how smoothly the shaft spins in the bushings. The more resistance the more amp draw and less rpm. To me over an 8 amp draw at 2 volts is pretty good.
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Old 04-13-2007, 04:24 PM   #3
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What if the motor is pulling only 4 or 5 amps? Is it a sign for something? Also why would it me a better motor if it pulls more than 8 apms, more torque ? Also would it affect the run time ?

Just curious...

F.
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Old 04-13-2007, 04:52 PM   #4
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I took apart the 8.2 UltraBird, and cleaned it up and re-lubed the bearings and its drawing 7.9 now...
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Old 04-13-2007, 04:59 PM   #5
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these numbers are all without a fan
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Old 04-13-2007, 05:00 PM   #6
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Quote:
Originally Posted by Jake S
I took apart the 8.2 UltraBird, and cleaned it up and re-lubed the bearings and its drawing 7.9 now...
beings that the motor might of have been dirty might be the reason it pulled higher.....with it all lubed up and spinning freely is when you will get the true numbers....

you can also check into different brushes and spring combination...

most guys will use the f brush with red springs + and -
i have tride all different types of brushes..i dont have a favorite..
but i mainly use 767.
you can go higher rate of spring like purple + and - but will have to gear the car like 1 tooth higher.

hope this helps...

matt
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Old 04-13-2007, 05:04 PM   #7
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more current = more heat. This test is completely irrelevent from a performance side of things.
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Old 04-13-2007, 05:20 PM   #8
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Quote:
Originally Posted by ixlr8nz
more current = more heat. This test is completely irrelevent from a performance side of things.

Well put...
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Old 04-13-2007, 07:16 PM   #9
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Jake, Those numbers would be good if it is a clean freshly cut motor but after you re lube them the numbers dropped because it is more efficent. That is the number you go by. Every time I buy a new cobalt the numbers are about 8 -10 amps but that is only because it is brand new and everything is tight. Honestly all my motors race ready are only about 7 amps. And when your motor is clean and free of any dirt that is when amps mean the counductivity of the motor and how much power is getting to the comm and to the wheels, but amps do also mean a faster battery drain because you are pulling more amps from the battery.
Hope that helps some
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Old 04-13-2007, 11:18 PM   #10
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all motors cleaned, i forgot to write the numbers down, but most motors gained .1-.2, while others lost up to .7-.8
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Old 04-14-2007, 12:43 AM   #11
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Quote:
Originally Posted by Jake S
all motors cleaned, i forgot to write the numbers down, but most motors gained .1-.2, while others lost up to .7-.8
i think the track is your best "dyno" .... i know someone who was only pullin 5 amps... but the car was a rocket and the motor was just awesome... so...

try putting your finger on the brushhoods and watch the amps go up if you squeeze lightly.
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Old 04-14-2007, 12:46 AM   #12
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yep i noticed if i pushed on the arm from the bottom the amps went up too... but its just to "rate" motors, i stand by that 767s with purples is the best combo in any motor, as it has supplied my best co27, my best monster stock, and my best ultra bird
After cleaning:

Monster1 8.91 (P+ P- 767+ 766-)
Monster2 7.97 (P+ P- F+ F-)
Monster3 7.33 (P+ P- F+ F-)
Monster4 6.87 (P+ G- F+ E-)

CO271 7.2 Amps (P+ P- 767+ 767-)
CO272 6.1 Amps (P+ G- F+ 766-)
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Old 04-14-2007, 12:47 AM   #13
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still gotta clean the ultrabirds though...its 2:45 and im tired....hah
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Old 04-14-2007, 02:11 AM   #14
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To be blunt - current draw under no load means nothing.
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Old 04-14-2007, 02:34 AM   #15
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Quote:
Originally Posted by sosidge
To be blunt - current draw under no load means nothing.

I agree 100%. I only run my motors on the charger to make sure they go and also to run in brushes etc. It never means anything performance wise with no load. Most of the top motor tuners agree that the track is the only place to fully tell how good a motor is.

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