Powering a 400v AC motor.

[timo]

I'm currently building an electric go kart, however i need help running the 400vac motor. I don't know how I can get to 400vac from a standard battery, i don't think 24v to 400v inverters exist yet. Can someone give me some tips on running that thing? (i can use any battery, i just need it to work)

 

[anickode]

That is a horrible idea.

And don't take this the wrong way, but the fact that you have to ask makes it an even worse idea.

Are you sure it's 400v and not 400hz?

 

[itsid]

nono, that's not too horrible at all, it's just a serious challenge

what you need is to step up from way less than 12V batteries
most electric cars nowadays run at 200 V (192 nominal IIRC)
Not too big of a deal to double that up...
dangerous as an unprotected spinning circular saw at your neck, but other than that ..

Okay, you can't do that with car sized starter batteries of course that'd weigh a ton,
with 3.2V batteries that's 60 in series to get to 192V and
therefor 120 in series to get to the 384 nominal (420 max volts) you are going to need..
with a single row you can't pull much,
so I'm guessing you're going to need about 20 or so rows
to get a decent amount of power

makes it 2400 cells
(allegedly cheapest decent ones are 2.50 each.. I paid 5 bucks a pop last for good ones... ..)

So anything between 6000 and 12000 dollars for the battery.

And? still interested?

thought so...

'sid

 

[anickode]

And being an AC motor, you'll need a VFD, not an inverter. An inverter supplies a constant frequency output, so your motor will only be single speed. (AC motors speed is dictated by frequency, not voltage), Without building a custom one, you'll be limited to a common bus industrial drive which allows DC input rather than AC. That'll set you back about 2 grand if you can find one.

It would be far cheaper to purchase a proper motor than to use what you've got and make it work. Not to mention way safer.