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Old 09-26-2015, 10:45 AM   #2086 (permalink)
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Originally Posted by e*clipse View Post
two important points:
1) rectified AC is not smooth DC. It's actually quite "lumpy." Basically what any rectifier does is invert the negative part of the sin wave to be positive. A full wave rectifier with a 60Hz sin wave input will have a 120Hz set of all positive waves (half wave lumps). It's not smooth DC yet; that will require further filtration.

Originally Posted by e*clipse View Post
Anyway, as shown in the drawings, one phase leg of the 3 phase motor will have current flowing through it. This current won't be alternating, as in reversing sign. However it won't be DC constant. Further, even if it were constant DC, current flowing in the phase leg would cause the magnets in the rotor to align with the stator. Yes, it won't rotate around, but it could move up to about 45 degrees in a 4 pole pair BLDC motor.

This is the main problem I see with using a BLDC motor. I don't think it would be an issue for an induction motor, because you wouldn't induce current in the rotor. I don't know how wye vs delta connection would affect it's operation in an induction motor. Perhaps there's a clever way to put exactly opposite currents into a BLDC motor such that a net zero torque could be produced? The charger would have to know the rotor's position and somehow connect to all three phases to pull that one off.

- E*clipse
Here in Norway we have 3-phase 400v, so that would make for a supercharger if 3-phase could be used - all built into the inverter without much extra cost.

Charging a 6-800v batterypack with decent range would take some time with a regular charget - not to mention the price tag on a charger of that scale.

If the controller can handle the charging too - that would be a great leap forward in DIY EV.

- Daniel
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