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AC vs Series DC efficiency

52K views 82 replies 20 participants last post by  gunnarhs 
I know, it is discussed before, but how do you think, how much difference is between AC 3 phase induction motor and DC series motor efficiency?
Hi Yohn,

Generally speaking for the size and power range of EV motors, I'd give AC about 2 or 3% advantage over DC. And then maybe a percent or so is given back in the AC controller versus the DC counterpart.

Towards the higher power end of the EV range, AC drives will run higher voltage systems like 300V batteries. There are some AC drives available now in the lower to medium power range rated for about 100V batteries.

That's the way I see it :)

major
 
Yet I hear that induction motors win the efficiency contest with PMs at light loads because they have control of the field. And you trade the mechanical commutation for electronic commutation in the AC-DC argument or in other words; replace carbon switches with silicon switches. So it is a tradeoff of efficiency, durability, cost and which type you are offering for sale, isn't it ;)
 
har har, that must be why I listed several downsides of each motor type, including magnet motors, right? The question is which is most efficient. I provided the correct answer.
You know magnet motor is the term used by the free energy community for the machine having no windings and your use of it is worrisome.
 
That's hilarious. You are right. I forgot about those folks. I was trying to avoid the BLDC, PMAC, PMSM letter soup.

So no data yet showing the superior efficiency of Induction motor as you claim?
You got me wrong. I did not say I favored any particular motor type nor am I out to prove anything here. I simply was pointing out you made a statement which is erroneous in the eyes of many experienced people in the field.

And the correct terminology to encompass all those motors would be simply PM meaning Permanent Magnet and it is understood that it is a PM field with a wound armature.
 
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