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Old 03-22-2003, 10:36 AM   #1
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Default Amp draw at Motor break-in

Guys;

With the purchase of an LRP Pulsar charger and the Motor run-in feature, I am now able to monitor the amp draw during break-in and running.

Question: Lower Amp draw at a set Voltage (3.0v, etc.) is better, Right? Logicly this should be the case, but maybe I'm not looking at things right.

Any experiences or opinions??

Thanks,
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Old 03-22-2003, 11:11 AM   #2
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Hey pops, I always break-in my motors at the 3.0v mark. The theory is (per big jim) that at higher voltages the break in process will only yield a higher blackening of the comm. I have a turbo 30 and find that most of the epic can stockers (minus the MHS) will have about 5.25-6.5 amp draw once brushes are completely broken. I hope that helps--Al
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Old 03-22-2003, 11:24 AM   #3
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Amp Draw during breakin is an indication of motor friction. The more friction the higher the amp draw. If you increase the motor brush spring tension you will find that the amp draw during breaking increases. Increasing spring tension and thus amp draw at idle may or may not improve on track power which is at considerably higher amp draw. If the bushings of a stock motor are well broken in and a good motor brush spring tension has been found with track testing, then duplicating this motor's amp draw by adjusting spring tension might be useful. I always prefer to measure the spring tension rather than using ampdraw during breakin, because there are other factors like bushing friction which affect the amp draw during idle.

The lowest ampdraw during breaking will occur with light springs. This might give very poor on track performance.
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Old 03-22-2003, 12:16 PM   #4
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pops,

with the lrp pular you really cannot monitor amp draw consistantly. the pulsar will automatically vary the voltage output to the motor ( no matter how you have it set) to get the lowest amp draw. You can check this buy running a motor at 3 volts and then check it with a dvm (volt meter) you will see that the setting on the pulsar and the reading on the dvm will be different.

The pulsar is really intended for running laths and so on you cannot use the amp draw readings to rate a motor because every motor will get a different voltage.
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Old 03-22-2003, 07:36 PM   #5
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Kingzj is right... my Pulsar doesnt read even close to my Turbo 35 with the same motor and settings... check the voltage like Kingzj says and you will see for yourself.
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Old 03-22-2003, 08:35 PM   #6
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Default Amp draw at Motor break-in

Guys;

I want to thank you all for your quick replies.

Thank you, Steven (popsracer)
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Old 03-22-2003, 11:13 PM   #7
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here is a better way to break in your motor.

Hook up your lrp to a slave motor (an old 540 will do) with the polarity reversed so the motor will run backwards.

use a piece of fuel tubing to connect the slave motor to your good motor.

use some rubber bands to hold both motors to a ruler or something similar.

start up the slave motor and let it run for about 5-10 mins on about 4volts. (don't forget to oil bushings on a stock motor!)

this works well and keeps your brushes and com in top condition for your next race
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Old 03-23-2003, 06:29 AM   #8
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You really should not do that to the newer stock motors with the built in capasitors. when you run a motor it acts like a generator and the power has to go somewhere and it can damage the capasitors. the best way to break in a stock motor is on a turbo 35 ( or similar ) at a lower voltage 1-3 volts for 300-600 seconds. then use a fiberglass cleaning stick and clean the com. You should try and not touch the brushes when using the com stick. On the newer Monster Stock motor you can do this by removing one of the hood screws and wire. You just want to avoid moving the brushes if at all possible.
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Old 03-23-2003, 06:48 AM   #9
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Alternatively, use a slave motor, disconnect one of the brushes and do what Dragonfire mentions. Repeat for the second brush. This gets rid of the generater effect.
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Old 03-23-2003, 09:26 AM   #10
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There is no problem with the capacitors if you breakin a motor as a slave. If you turn it the wrong way the shottky diode will tend to short it and it will be hard to turn. If you turn it the same way it runs on the track, the current produced is no different than coasting on the track. The slave motor setup for breakin reduces wear on the comm. It is helpful to clean out the comm slots after breakin, when using the slave motor setup.
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Old 03-23-2003, 01:21 PM   #11
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this is a long overdue thread. props to pops! every sunday i have to hear how someone's motor is drawing ridiculous current, and the subsequent quest for others to match that. a fundamental, but interesting, point is that a higher current drain is indicative of friction somewhere. now it's up to the user to determine if the friction is brush related or bushing related. or heaven forbid, debris in the can! though this test is a crude way of evaluating a motor, it can, as john pointed out, serve as a relative tuning aid for each motor. half diagnostic, half empirical.

something i've used it for is to get an idea of the impact of com drops. duration and magnitude of the lubricity. though i haven't kept any data regarding this subject, it is fun to test types, and application methods and quantities. just an fyi and possible probe into whether anyone has some data on the subject.
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Old 03-23-2003, 01:53 PM   #12
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Want high amp draw from your motors???? stick a screwdriver in the cann btween the stacks....... enough amp draw to shut down any charger with a motor run feature...... now that's power baby!!!!!

Buy a real dyno or use the best dyno in the world............ the track!!!!!!!!!!!!
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Old 03-24-2003, 11:33 AM   #13
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Default Buy a real dyno

IMPACTPLAYR;

1) I have a REAL Dyno. (Robitronic) DO YOU!

2) I disagree about the Track being ones Dyno. Unless you have access to a personal lap timer and an open track to practice on. It can be very difficult to gauge the performance of changes. And for the most part, not too many of us are Pro Drivers that can run perfect lines lap after lap, so some of the variables need to be removed to accurately make comparisons.
But hey, this is just MY opinion.
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Old 03-24-2003, 02:31 PM   #14
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No I don't have a dyno, but and I don't hold much stock in them anyhow....... BUT they are far better than reading amp draw from the motor run feature. However I do know that motor preformance can be felt on the track w/o having any form of lap timing system... UNLIKE suspension changes if the motor feels fast it is fast....period....
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Old 03-24-2003, 05:33 PM   #15
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Quote:
Originally posted by IMPACTPLAYR
No I don't have a dyno, but and I don't hold much stock in them anyhow....... BUT they are far better than reading amp draw from the motor run feature. However I do know that motor preformance can be felt on the track w/o having any form of lap timing system... UNLIKE suspension changes if the motor feels fast it is fast....period....
Not true...I have tuned motors that looked ballistic, but the lap times were not there, I have also tuned motors that felt and looked slow but were fast. You can make some deductions about high amp draw. At times high RPM is in direct relation to high amp draw, not always but enough to be considered.
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