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Old 10-03-2003, 04:42 PM   #1
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Monster amp draw

I have a monster stock "PRO" that I'm messing with...(so much for the idea of getting a decent factory dyno tuned motor)...and after cutting the comm, new E brushes, playing with springs etc my LRP Pulsar says I'm pulling 7.5 amps @ 5.0v

The motor appears to be producing very good rpm's and it's not arcing like mad...You think I'm good to put it back in my 12th scale with a 7.5 amp draw
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Old 10-03-2003, 05:01 PM   #2
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I'm getting a constant 9.5 amp draw on all my Monster Pro with only 3.0v.

Dan
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Old 10-03-2003, 05:15 PM   #3
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I'm not really sure on what amp draw is good for it, but as for putting it in a 1/12 scale, absolutely. From the running I've done with it in my 12L3, the Monster seems to be BORN for 1/12 scale cars(a car that light doesn't need all the torque that a 1/10 scale touring car does)......
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Old 10-03-2003, 06:08 PM   #4
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Thats what this motor is going in Grizz...a 12L3, I just got mine and all the STUFF to make it go

So 9.5 @ 3.0 huh....hmmm I gots some power happening then maybe. Frickin thing was supposed to be Dyno Tuned outa the box...no tweaking required....yea uh huh...it was spitting and sputtering, pulling 3-4 amps, arcing like Ben Franklin in tinfoil panties Next time I'll just get the plain jane version....
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Old 10-03-2003, 06:32 PM   #5
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Quote:
Originally posted by SteveG
Thats what this motor is going in Grizz...a 12L3, I just got mine and all the STUFF to make it go

So 9.5 @ 3.0 huh....hmmm I gots some power happening then maybe. Frickin thing was supposed to be Dyno Tuned outa the box...no tweaking required....yea uh huh...it was spitting and sputtering, pulling 3-4 amps, arcing like Ben Franklin in tinfoil panties Next time I'll just get the plain jane version....
Run the trinity 4499 with red & greens, smooth out the bushing and after you cut the comm, put a drop of matrix lube in the comm and bushing. It'll help breakin the brush within 30 seconds and then you should start seeing the amp draw increases. Good Luck.

Dan
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Old 10-03-2003, 09:35 PM   #6
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Once the brushes are fully "seated" check hood alignment. A friend gave me a tuning tip for 1/12 scale take a little off leading & trailing ends off brush and slot it. I didn't slot it . I drilled a hole. It worked for me... FAST
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Old 10-03-2003, 09:42 PM   #7
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Myself and a bunch of people I race with least year would pull 12amps at .9 volts with our Promatch 19 turn Motor. Thank God the GFX came out so it would not draw to many amps and shut the charger down. It took for ever to break in a motor.

I got motors that are 2-3 years old and pull about 7.5amps at 2.5 and 3 volts. Never buy the Tuned Dyno Motors... there is nothing special about them They say Diamond Trued and so on but that is a bunch of BS. I gave Chad about 4 Arms last year at snowbirds from motors that were suppose to be trued... they were not and very out of round. One Arm was so bad that the winding made it so that the arm would not spin in the can and that was suppose to be a Pro Dyno Tuned Motor that I won. I got 3 Motors out of the dela after I talked to Chad about how a Dyno Tuned motor got through their quality contol like that.
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Old 10-04-2003, 04:13 AM   #8
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can someone explain the amp thingy? like whats better and what the voltage does?
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Old 10-04-2003, 04:39 AM   #9
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lower amps is better as the motor is more effeciant and has low resistance.
a motor that has high current draw is less efficiant and has a high resistance.
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Old 10-04-2003, 08:27 AM   #10
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A motor that is pulling more amps is faster, but that is deceiving beasue you can put your finger on the shaft as it is spinning and cause the motor to draw more amps.

Lower amps are not better. For a Stock Motor...if the brush hoods are not alligned and the Comm is not cut then you are going to draw less amps then you would if the brushes were centered and the Comm was cut...What TRF says makes no sense. The High resistance of turning the comm by hand is actually good...not bad.

Trust me... if you look at two motors... you want the one that is drawing more amps...cause it is closer to being setup correctly then a motor drawing less amps seeing that they are both not binding.

True track performance is where it all matteres though.. BUt if I take a Monster Sotck that is pullling 4amps at 3 volts and take my monster stock that is turning 12amps at 2 volts... the 12 amp one will be faster, more punchy, and run a longer then the one that is pulling 4 amps.
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Old 10-04-2003, 06:58 PM   #11
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I don't understand! Are u saying that a motor with heavier tension springs will always be faster then one with light spring, due to the fact that the heavy spring creates more amp draw. Certainly a motor with bushings will not be faster then one with bearings.

The highest amp draw i could achieve with my monster stock was 7.1 amps @ 3 volts and I can assure u the brushes were not aligned when i got that figure.

A motor that has unaligned brushes will arc more and be less efficient and will therefore draw more amps. Is this correct?

If not, then how are u guys getting such high amp draw numbers.
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Old 10-04-2003, 07:13 PM   #12
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Default Efficiency vs Amp Draw.

Rowdy;

Not necessarily in a DC Motor. Amps is Current flow. Arcing Brushes cause LESS current to FLOW through the Motor, so LESS amp draw.
My very best Monster Stock, pulls almost twice the current of my average MS Motors.

Heavier Springs are to reduce Arcing at the Com and the Power loss that goes with it. Too much Spring Tension only increases drag and wear on the Com.

From Dyno testing, I have found little or no Power increase with Bearings over Bushings. The maximum RPM difference is also very little. What's significant is, drag is reduced with Bearings, so Spool-up time is much quicker.


Last edited by popsracer; 10-04-2003 at 07:24 PM.
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Old 10-04-2003, 07:56 PM   #13
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so how do u acheive such high amp numbers?
The highest I could get with the brushes aligned was 5.5amps @ 3volts with a fresh comm, and as i stated above I could get 7.1amps @ 3volts when the brushes weren't aligned.
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Old 10-04-2003, 08:09 PM   #14
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Default Monster amp draw

Rowdy;

Unfortunately picking a Motor is like fishing, sometimes you get a good one, but most of the time you probably should throw them back.

Seriously, I truely believe that a GREAT Stock Motor is maybe 1 or 2% out of 100, most are just average and the rest are Dogs.

Tuning can make any Motor better, but a Dog will still be a dog. This assuming that they all have properly aligned Hoods and correct Shimming. Don't take much stock in the Dyno labels either unless they are from a private Motor tuner.
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Old 10-04-2003, 09:09 PM   #15
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Quote:
Originally posted by trf racer
lower amps is better as the motor is more effeciant and has low resistance.
a motor that has high current draw is less efficiant and has a high resistance.
no,lower resitance means higher amp draw.
Ohm's Law:
V=IR lower resistance,constant voltage=higher current.of course we are talking about eletrical resistance and not mechanical friction.
a motor that is jammed or held from spinning will most definitely draw amps like crazy,but we are assuming none of us are donig that when measuring!
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