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e*clipse · 09-04-2014, 04:31 PM

With a dyno, we still need a HUGE load dump. Pump water? Heat water?

One thought I had was to just build the car in my case with just the front motor. Build the controller so is could supply about 50% more than the rated power ( 75 kW?? ) Measure everything really well, and go do some slow drag races. F=ma. Step the controller's power limit up each run, and allow a LONG cool-down time.

I know that's no help for ***engineering*** stuff, but it would help for my multiple motor design.

Would knowing the stator winding be any help? Back at post #12 I showed some pics of the stator windings. Each phase is a bundle of 12 wires the measure 0.032" OD. (measured with Brown & Sharp calipers) I have no idea what the insulation thickness is.

Knowing the winding diameter gives some interesting information:
American Wire Gauge table and AWG Electrical Current Load Limits with skin depth frequencies and wire breaking strength
for 0.032, AWG20 wire: 10.15Ohms/1000ft 11A max chassis 1.5A max power 27 kHz
for 0.0285, AWG21 wire: 12.8Ohms/1000ft 9A max chassis 1.2A max power 33 kHz

I'm assuming "power" wiring is continuous, "chassis" wiring is for short-term bursts. I'm assuming for motor use, they're using someplace in between because these wires are bundled and can't dissipate heat like a single strand.

So, using the AWG 21 #'s, 12 strands * 9A = 108A.

It's also unlikely that a Japanese company is using AWG wire. The size is VERY close to 0.75mm.

Has anyone compared motor current limits or power ratings to the winding diameters? ***HEY*** Those ORNL papers might have something about this. They did push them harder than spec in the tests with a real dyno.

09-04-2014, 04:31 PM	#60 (permalink)
e*clipse Permanent Apprentice Join Date: Jul 2010 Location: norcal oosae Posts: 523 Thanks: 351 Thanked 314 Times in 215 Posts	With a dyno, we still need a HUGE load dump. Pump water? Heat water? One thought I had was to just build the car in my case with just the front motor. Build the controller so is could supply about 50% more than the rated power ( 75 kW?? ) Measure everything really well, and go do some slow drag races. F=ma. Step the controller's power limit up each run, and allow a LONG cool-down time. I know that's no help for *engineering* stuff, but it would help for my multiple motor design. Would knowing the stator winding be any help? Back at post #12 I showed some pics of the stator windings. Each phase is a bundle of 12 wires the measure 0.032" OD. (measured with Brown & Sharp calipers) I have no idea what the insulation thickness is. Knowing the winding diameter gives some interesting information: American Wire Gauge table and AWG Electrical Current Load Limits with skin depth frequencies and wire breaking strength for 0.032, AWG20 wire: 10.15Ohms/1000ft 11A max chassis 1.5A max power 27 kHz for 0.0285, AWG21 wire: 12.8Ohms/1000ft 9A max chassis 1.2A max power 33 kHz I'm assuming "power" wiring is continuous, "chassis" wiring is for short-term bursts. I'm assuming for motor use, they're using someplace in between because these wires are bundled and can't dissipate heat like a single strand. So, using the AWG 21 #'s, 12 strands * 9A = 108A. It's also unlikely that a Japanese company is using AWG wire. The size is VERY close to 0.75mm. Has anyone compared motor current limits or power ratings to the winding diameters? *HEY* Those ORNL papers might have something about this. They did push them harder than spec in the tests with a real dyno.