leitmotif
Member
Am teaching a class Oct 18 and 25 Basic VFD and 3 phase motor applied to electric vehicle.
Have VFD and motor setup made by Fuji for GE field demos (thank you Steve Bailey).
VFD is GE AF 300 B rated 1/2 HP 230 VAC
Motor is Fuji 1/4 HP 200 VAC 3 phase 1800 RPM
Built model car to demonstrate VFD and motor operation start stop accel decel etc etc. Works fine on level smooth floor. Motor drives car via 28:1 gearbox (not a worm) and then a 20 tooth driver and 30 tooth driven gears.
Factory VFD and motor setup works just fine and braking works. Set on bench and wrapped line on gearbox output shaft (5/8) and lifted and lowered 100 lb weight. Braking was tested with 50 lb weight. Started in downward at 60 Hz and dialed freq back to 30 or 40. Slowed and held load fine. Further dial down to say 5 or 10 resulted in loss of braking and load runaway. Unfortunatelly I did not measure braking voltage in this testing.
Want to demonstrate regen braking and use lites to show when regen is active. Problems at this stage:
1. Model car lacks traction (with heavy load drive wheel breaks loos and car skids down ramp). Working on that.
2. Only value I know for existing braking resistor (factory stock "default" is 180 ohm. Do not know voltage produced under braking, do not know wattage value for brake resistor.
3. Based on ignorance in #2 I have no idea of how many 60W 120 VAC lites 17.7 (cold) ohms I need. Picked these as an arbitrary starting point - can change lite bulb parameters as / if needed.
4. Have enquiry into GE local rep have not heard back yet.
5. Tried forum search "braking resistor values" "braking resistor" no luck.
Using car to demonstrate regen may not work (may not overcome traction problem and may have to have very heavy load - toting 400 lbs to class is not attractive). Motor gearbox as capstan may be only option. While mechanically this is no different than a car students may not easily recognize it is the same - trying to make class as "student friendly" as possible.
Still want to demonstrate the regen action using lite bulbs. Open to ideas suggestions or other illuminating thoughts.
Dan Bentler
Have VFD and motor setup made by Fuji for GE field demos (thank you Steve Bailey).
VFD is GE AF 300 B rated 1/2 HP 230 VAC
Motor is Fuji 1/4 HP 200 VAC 3 phase 1800 RPM
Built model car to demonstrate VFD and motor operation start stop accel decel etc etc. Works fine on level smooth floor. Motor drives car via 28:1 gearbox (not a worm) and then a 20 tooth driver and 30 tooth driven gears.
Factory VFD and motor setup works just fine and braking works. Set on bench and wrapped line on gearbox output shaft (5/8) and lifted and lowered 100 lb weight. Braking was tested with 50 lb weight. Started in downward at 60 Hz and dialed freq back to 30 or 40. Slowed and held load fine. Further dial down to say 5 or 10 resulted in loss of braking and load runaway. Unfortunatelly I did not measure braking voltage in this testing.
Want to demonstrate regen braking and use lites to show when regen is active. Problems at this stage:
1. Model car lacks traction (with heavy load drive wheel breaks loos and car skids down ramp). Working on that.
2. Only value I know for existing braking resistor (factory stock "default" is 180 ohm. Do not know voltage produced under braking, do not know wattage value for brake resistor.
3. Based on ignorance in #2 I have no idea of how many 60W 120 VAC lites 17.7 (cold) ohms I need. Picked these as an arbitrary starting point - can change lite bulb parameters as / if needed.
4. Have enquiry into GE local rep have not heard back yet.
5. Tried forum search "braking resistor values" "braking resistor" no luck.
Using car to demonstrate regen may not work (may not overcome traction problem and may have to have very heavy load - toting 400 lbs to class is not attractive). Motor gearbox as capstan may be only option. While mechanically this is no different than a car students may not easily recognize it is the same - trying to make class as "student friendly" as possible.
Still want to demonstrate the regen action using lite bulbs. Open to ideas suggestions or other illuminating thoughts.
Dan Bentler
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