# Shinwa motor dresser tool



## cwbam (Feb 8, 2010)

Does anybody know anything about this tool?

http://www.ebay.com/itm/shinwa-moto...racter_Radio_Control_Toys&hash=item4abdea9fda


Is it for 1/24 armatures? 
complete motors? of all sizes?

thank you


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## RACERMAN (Nov 1, 2007)

it is for complete rc motors but i converted mine to do 1/24th.
GARY


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## slotcardan (Jun 9, 2012)

The truth is it's snake oil. Really worthless for motor tuning because you are not testing a motor at the usual running voltage and average load. To tune a motor any readings must be done at the voltage the motor will see while under usual load.

The shinwa gauges cause you to tune the motor perfectly for a zero load situation. Usually you set the brush tension way to soft. The timing gauge is worthless unless you took a reading when it was new. Most modern motors have timing marks.

You can avoid the waste of money by water dipping the motor for break in, taking it apart, cut the comm then second water break in to fully seat the brushes to the new smaller contour. Cutting the comm increases timing 2-4 degrees if the motor has preset timing angle, a motor with zero timing will see no change other then a fresh comm surface.

The shinwa will make you aim for high Rpms at a lower voltage at no load. When you toss the car on the track for a lap it will run terrible.

You can see some motor degradation on the shinwa but it just means cut the comm again.

You can do that without a shinwa.

The only dyno worth anything was the competition electronics dyno, or to a lesser extent the tekin motor dyno, both used slave motors to generate load for testing. The tekin calculated the power coefficient of a electric motor which allowed you to generate a decently accurate rpm and torque spec for a motor.


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## cwbam (Feb 8, 2010)

Thank you!!!!

I remember a few years ago asking about rpm's on slot cars. 
NO ANSWER from good racers. 
Then I remember load & no load speed on Milwaukee drills and power tools.

ITS LAP TIMES that's important, 
a good handling car that you can run lots of good fast laps.


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## slotcardan (Jun 9, 2012)

I've restored blown shinwa motor dressers and I have restored some odd ball rc dyno equipment more for nostalgia then anything else. Unless the equipment can calculate the power coefficient of a motor it's really worthless.

Vrp makes a nice dyno for hO scale because it reads the motor Rpms from the rear tires under some load, if you have a amp meter on it then you can approximate the power coefficient but for hO scale on most chassis there isn't much you can do other then making sure the brushes are set square on the comm and 180 degrees apart.

For those interested in fixing most 1980s rpm readers and testers they worked on the less common PNP power transistors. Most modern version use NPN transistors. The transistors were all rated for 5-15 amps most tuned 540 motors will pull that under no load so the transistors blow up.

For a rc car you want to test at 7.2 volts at 20 amps of load this is where most motors will spend 80-90% of the time. For offroad you want to test at 25-30 amps of load. You can see that requires pretty heavy duty amp control that almost no equipment can handle.

The early shinwa actually used 1 amp power transistors so it was like a joke with almost any motor. Later they went to 5 amp transistors. The last generation had 7 amp transistors and. 5 amp fuse.


It should be noted brushless motors have changed how dynos work... So more recently there have been very few motor dynos on the market. The only ones that make sense test power at the rear tires like a real car dyno.


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