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Motor performance information

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#26 Lucky2


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Posted 22 October 2023 - 12:36 AM

The first two revolutions are skipped. So, revolution count 1 is really the third revolution.

The "Flywheel Rpm" at revolution count 1 is usually between 3800 and 4000 Rpm.

Electric motors start up very quickly.


Notice at the top right corner of the graph. The verticle axis can be set to Flywheel or Motor Rpm


Please review the graphs and other texts again.  If you would like more help,  please call me.


Why has the Score Value been replaced with the Percentage Value ?
The original software showed only the Rpm values for each motor tested.
People (the doubters) said the Rpm values don't prove that a motor will
perform well on the track compared to the other motors of the same type.
They were asking for the software to predict the Lap Time.
So, the Score Value was added to the software because it is related to the
Lap Time.
Twelve machines were sold in 2020.  Each person was taught how to operate
the machine and how to use the Score Value.
After using the Dyno a few times and running the motors on the track.
They agreed that the Score Value is related to the Lap Time and is useful.
After the Slotblog experience,  I talked with a few owners about using the Percentage
Value.  They agreed because they just look at the Rpm for each motor and race the
ones that have the highest Rpm Values.
The Percentage Value helps them sort the motors into two groups. The motors
that test 4% or slower are not used.
Remember the reason that the Dyno was made: To help people find "Good" motors.
You know the story already.  Motors are purchased.  Powered at 5 volts with no load.
The motor with the greatest current draw is the best ?  So the best motor is installed
in a car and the Lap Time is shown on the monitor.
What could go wrong ?  Driver performance, Car performance can vary and the
motor in the car may not be the best because the Current draw test at 5 volts from a
free spinning motor is not related to the motor's ability to move the car around the track
Look carefully at the spread sheet.
Then the racer complains "I can't find any Good motors".  When I ask him to let me
test some motors.  The answer is "Those things don't work".
What else could go wrong ?  The Motor Lottery.  The motors vary from 6 to 10 percent.
The motors are mass produced and not made for use in Slot Cars.
So, maybe about half of them will be better than 3-5 percent ?  If 10 motors are purchased,
at least 5 should be good, right ?
Testing these 10 motors on the Dyno shows how many are good.
Example:  Five motors were purchased and tested on the Dyno,  4 were 3% or better.
5 more motors were purchased from the same hook on the wall. Only 2 were bettter
than 3%.  But, the best motors were found.
Ok, but some people do find good motors. Although is takes time to solder on pinion
gears and install the motors in the car.  Then hours at the track to test 5 motors.  While
the tires wear and the track temperature changes.
They wonder why the Lap Time is slow.  The Current Draw test said that the motor is fast.
Using the Dyno,  20 motors can be tested in 1 hour.  The good motors, maybe 8-10 are
ready to go on the track.  If there are a lot of people attending the race,  track time is
is limited.  The limited time can be used to test tires and gear ratios,  not motors.
It is common for a Dyno owner to test 20 to 50 motors and take only the 2 percent or 3
percent motors to a big race.
Phil Blanke    714 330-8239   cardura.instr@gmail.com

Attached Images

  • C1001 HAWK 7 Motors Range.jpg
  • D1002 Phoenix Motors Range.jpg

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Phil Blanke

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