Search found 253 matches

by devin
04 Mar 2018, 14:23
Forum: General
Topic: General questions
Replies: 12
Views: 1330

Re: General questions

i agree with rew if you lower the gear reduction to 2:1 or increase the battery voltage, then 15mph should be possible, but using 3:1 reduction, 90mm tire, 24v battery, then I believe (as rew seems to confirm) 15mph would not be possible. I do have a question for rew... what happens if he uses 3:1 g...
by devin
03 Mar 2018, 20:54
Forum: General
Topic: General questions
Replies: 12
Views: 1330

Re: General questions

Subject : Electric skateboard 1. I bought this motor: https://diyelectricskateboard.com/collections/electric-skateboard-motors/products/electric-skateboard-motor-6355-190kv and I also have a 6S lipo battery, does it enoght to bring me to 15 mph? I will now give you my opinion whether the board you ...
by devin
02 Mar 2018, 20:56
Forum: General
Topic: Vesc in ebike
Replies: 5
Views: 608

Re: Vesc in ebike

22.247448v PWM Effective V * 22.47448a Motor Current = 500w electrical = 13.88a battery amps * 36v (22.47448a Motor Current * 22.47448a Motor Current) * 0.1ohm = 50.51022w ohmic Heating (@ 2000rpm, assuming 100kv, 13.88a batt limit, 70.71a motor limit) 2.146154751251963931499 newton meters torque *...
by devin
27 Feb 2018, 17:45
Forum: General
Topic: Vesc in ebike
Replies: 5
Views: 608

Re: Vesc in ebike

devin just told you how to turn your motor into a 500 W heater. Don't listen to him. First: Motor current is proportional to motor load. If you don't put a load on the motor it will not draw a lot of current. In what situation did you measure the motor current? Second: The 1.5 A and 1.7 A you menti...
by devin
27 Feb 2018, 10:39
Forum: General
Topic: Vesc in ebike
Replies: 5
Views: 608

Re: Vesc in ebike

my understanding is this... for example If you want 500 watts at all rpms... Step 1: Detect the winding resistance with the vesc, then double this number because the Vesc detects the resistance from one lead to the center of the motor (virtual ground point), but you want to know the resistance from ...
by devin
07 Feb 2018, 19:06
Forum: General
Topic: Calculating motor heating?
Replies: 4
Views: 414

Re: Calculating motor heating?

thanks. any tips on calculating or estimating iron/core loss? switching loss? what are the factors I should use to guesstimate? once i have an estimate for core loss and switching loss, is that subtracted from the mechanical watts or added to the electrical watts/battery amps, etc? do my above calcu...
by devin
06 Feb 2018, 20:11
Forum: General
Topic: Calculating motor heating?
Replies: 4
Views: 414

Re: Calculating motor heating?

Also, if I have an electric skateboard with a 50v battery, and a 90kv (90 max rpm per volt no-load) hub motor which is 0.1 ohm lead-to-lead, and a reprogrammable VESC electronic speed controller.... & in the reprogrammable settings for the electronic speed controller, my friend chooses the follo...
by devin
06 Feb 2018, 20:09
Forum: General
Topic: Calculating motor heating?
Replies: 4
Views: 414

Calculating motor heating?

I wanted to calculate the joule heating while the motor is in motion and putting out mechanical watts (before calculating iron loss). Are my calculations correct? If I have a 90kv BLDC hub motor which is 0.1ohm lead to lead, a 50v battery, ESC with 20a motor amp limit, 20a battery amp limit, present...
by devin
20 Dec 2017, 04:05
Forum: General
Topic: "Peak Efficiency" Control Mode?
Replies: 110
Views: 14699

Re: "Peak Efficiency" Control Mode?

Where: D= 16.94 = Back EMF Voltage E = 18.821618 = PWM Effective Voltage Simply because 16.94V Back EMF Voltage is 90% of the applied 18.821618V PWM Effective Voltage, it follows that instantaneous electrical to mechanical conversion efficiency is also 90% . K= 90 = Desired Efficiency % Setting M= ...
by devin
19 Dec 2017, 18:15
Forum: General
Topic: "Peak Efficiency" Control Mode?
Replies: 110
Views: 14699

Re: "Peak Efficiency" Control Mode?

Where: M= 100 = Throttle % Setting K= 90 = Desired Efficiency % Setting L= 500 = Desired Min Watts Available Setting P= 4500 = Desired Max Watts Available Setting G= 48.2 = Battery Voltage D= 16.94 = Back EMF Voltage F= 0.025 = Winding Resistance Ohms Y= 120 = Max Motor Amps Z= 95 = Max Duty Cycle ...

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