X-File: Understanding VESC: the difference between "battery amps" and "motor amps"
#41
i agree, but the motor amp value is a fraction of a second but the battery amp value is whole second avg motor heating

",0,0,http://www.electric-skateboard.builders/t/understanding-vesc-the-difference-between-battery-amps-and-motor-amps/15995/78,2017-01-17 04:57:56 UTC
Reply
#42
in simple terms:

motor heating always equals battery amps, not "motor amps"

",0,0,http://www.electric-skateboard.builders/t/understanding-vesc-the-difference-between-battery-amps-and-motor-amps/15995/80,2017-01-17 05:04:08 UTC
Reply
#43
but we're assuming no hardware damage for the software thought experiment...

,0,0,http://www.electric-skateboard.builders/t/understanding-vesc-the-difference-between-battery-amps-and-motor-amps/15995/82,2017-01-17 05:12:49 UTC
Reply
#44
348 amps "motor amps" avg in 28.8% of one second does the same work (wattage) as 100 amps avg for a whole second "battery amps"

",0,1,http://www.electric-skateboard.builders/t/understanding-vesc-the-difference-between-battery-amps-and-motor-amps/15995/84,2017-01-17 06:07:25 UTC
Reply
#45
348 motor amps @ %28.8 sec = 100 battery amps = 5000w / 50 V

,0,1,http://www.electric-skateboard.builders/t/understanding-vesc-the-difference-between-battery-amps-and-motor-amps/15995/86,2017-01-17 06:09:02 UTC
Reply
#46
motor heat = 100 "battery amps" = 348 "motor amps" @ %28.8 of the time @ 50V @ 0.0415 ohm @ 5000w @ under 200rpm

",0,0,http://www.electric-skateboard.builders/t/understanding-vesc-the-difference-between-battery-amps-and-motor-amps/15995/88,2017-01-17 06:11:51 UTC
Reply
#47
in simple terms:

theory ?: to eliminate confusion i propose "motor amps" become named instead "ON PULSE AVG AMPS" while "battery amps" becomes named simply "AMPS"

",0,0,http://www.electric-skateboard.builders/t/understanding-vesc-the-difference-between-battery-amps-and-motor-amps/15995/90,2017-01-17 06:25:17 UTC
Reply
#48
@raphaelchang i assume in the DC PWM picture you posted with the green (A) current and pink (V) voltage graphs...

the reason the GREEN DC PWM doesn't look like nice straight even ramps is because there is a capacitor somewhere in the circuit...

would you say this is correct?

",0,0,http://www.electric-skateboard.builders/t/understanding-vesc-the-difference-between-battery-amps-and-motor-amps/15995/91,2017-01-17 06:41:35 UTC
Reply
#49
@raphaelchang without the capacitor, would it resemble ramps much more closely?

",0,0,http://www.electric-skateboard.builders/t/understanding-vesc-the-difference-between-battery-amps-and-motor-amps/15995/93,2017-01-17 06:57:23 UTC
Reply
#50
Hummie, post:94, topic:15995 Wrote:Could the increased motor amps explain why the motor is more inefficient at Lower speeds?

brilliant observation! Big Grin

",0,1,http://www.electric-skateboard.builders/t/understanding-vesc-the-difference-between-battery-amps-and-motor-amps/15995/95,2017-01-17 07:15:43 UTC
Reply


Forum Jump: