I’m guessing remove the belt so it spins free
Based off of that setup I would estimate a kV of around 165-170. I just put in all the non variables in to esk8 calc and then adjusted the kV until it reached ~57k erpm and it was saying 36.9mph and 165kV
Which is what I came up with. But my motors are supposed to be 190kv. I think they were incorrectly rated.
Are you using the right equation?
Kv = RPM / ( Voltage – ( Current * Rm ) ) Rm being the motor resistance through one phase
The best way to measure kv imo, is to grab a drill and connect it to your motor shaft. Then attach an oscilloscope to two of your phase leads, measure the peak voltage and period of the sine wave then use this equation:
*RPM = ((1/period)60)/(pole pairs) Kv = RPM/(peak Voltage * 0.95)
The 0.95 is a fudge factor used by industry…
If you don’t have an oscilloscope, you can use a multimeter in ac mode and a tach to measure rpm. The equation you want to use then is:
Kv = RPM/(Voltage * 1.414 * 0.95)
The voltage you measure has to be multiplied by 1.414 (square root of 2) because the voltmeter measures rms voltage and not peak to peak. The 0.95 is again, a fudge factor used by industry.
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You forgot that your duty cycle is not 100% So it’s really closer to Unloaded [email protected] Loaded [email protected]
But this doesn’t take into account losses due to motor resistance as stated in my previous post which I think is the bigger issue
You guys have much bigger balls than I for wanting to 40mph on these boards. 25mph on my board feels like warp speed to me…and I used to race motorcycles.
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I know. But I feel like they are about 20kv lower than they should be.
Fastest I’ve been on flat land is 44mph to me 30+ is warp speed and required alot more concentration. 20-25 is cruising
The roads around here are smooth like butter. 30 is good. Above 35 is for sure more concentration.
I’m going 200kv with two 6372 motors pulling 15T - 38T ratio on custom double idler @marcmt88 mounts and Evolve Super Carve sliding MBS 100 mm wheels…
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Agreed, honestly anything beyond 25 mph on a board is to much