What is the current and best method for determining brushless motor winds?
My volt meter’s ohm setting may not be up to par/accuracy.
I have heard Fluke or Istek or BK meters will do the trick , measuring from pole A to the timing ring.
I ask in this forum, as onroad seems to be more it tune with this sort of thing.
There have been some suspicious comments about a few local cars being fast , and I wish to put an end to that asap.
Hi,
You, yourself, can establish a baseline tied to your specific device and the specific motors and their specific testing voltages at a particular frequency/temp/run-time-to-sample-interval using an inexpensive ($100 or less) DMM with inductance/LCR capability:
https://www.amazon.com/Multimeter-Re.../dp/B00Q2CF5QO
https://www.walmart.com/ip/DMM-Digit...&wl13=&veh=sem
If those units seem stable on milli-ohm measurements, as well, you can factor in the static resistance to your impedance points gleaned from the above processes.
You'd also have to decide if you're going to bring rotors into the equation, because their presence in the stator's magnetic field will change readings substantially.
In other words, from careful and repeated testing of many motors of several different "winds" you can provide a picture of what an "average" 21.5T (or any other motor) would look like when tested on your equipment with the same criteria. This is actually very precise for your sample sets, although probably not accurate against the aforementioned secret measurements.
So, the largest investment would be your time in reading up, testing (if everybody will agree to it) and plotting your results.
Even if you shell out several hundred dollars for dynamic inductance unit, you'll still need to test against the above criteria and equate that to: turns of wire of a certain gauge? rotor composition? wind pattern? presumed length of the wire? ...
The end result will be simply testing the racers' motors before events and having a cap on an overall inductance:resistance quotient and/or rotor size/composition - which is really the historic issue all over again, except not focused on wire diameter/length as actionable points.
I'm not bashing your idea AT ALL, I find it very interesting, you'll just need to get an easily repeatable process going and sell it to your club.
I would offer this: get a used dynamometer and a cheap oscilloscope and simply measure the motors at a certain voltage and phasing frequency. Don't worry about amps drawn or any of that, just use the same setup all the time for all measurements.
The only important criteria are the voltage and switching frequency against a particular load. About the temps, bring them up to 5-10F above ambient with a hair dryer prior to testing and then forget about it.
You won't have to spend much, study much or argue much if you simply present this as a leveling opportunity. If they grab their lexan scissors and Xacto knives...drop the subject
Gene