# Old vfd, DC-DC converter & ?



## adeyo (Jun 6, 2012)

Okay, so I picked up a few old-school items from a friend. I want to know what they have any of these I might be able to incorporate into my project. Can I modify this old-school 15 hp VFD? ( Somehow increase the horsepower rating?) It wouldn't have all the bells and whistles but could it do what I need to drive a vehicle?

Also, this thing with the cobwebs I have no clue what it is? (Disregard the black wire, i just tossed it there)Is it possibly another VFD?

Finally, I got two DC-DC converters ...one is 48v to 24 another is b/w 102-130v to 6 (+- 5%) ...Can these be used? 

My plan is an ac motor conversion of approx 30 HP or so....still fighting out what to do voltage wise. Go high (more$$ batteries) or keep it at either 72 or 144?


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## adeyo (Jun 6, 2012)

The above old controller is rated 3ph 440v 25 amp. 15 HP ...does that mean these are maximum or continuous rating? Also, what does this mean about my motor selection to make sure it works with my controller? (Thinking of going go-kart the same way I would a vehicle just to learn more about the ac system to prepare for my ev, i also have a separate DC-DC converter)


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## PStechPaul (May 1, 2012)

I really doubt that you would be able to use the old controllers and other devices you got. Basically, if you don't know enough to figure out what they do and how they operate and are able to test them, you don't know enough to modify them for something other than what they were designed for. And it's hard to find schematics and parts for such old equipment.

For maybe about $100 you can get a 2HP AC motor and VFD and use them for a go-cart or tractor. You still need to get the high voltage like 250VDC minimum, but you might be able to do that with a DC-DC converter for such low power. I built my own but you should be able to use something like this:

http://www.ebay.com/itm/320800175307?ssPageName=STRK:MESINDXX:IT&_trksid=p3984.m1436.l2649

I have one on order and I'll post the results of my project which uses a 2HP VFD and three phase motor in a riding mower/tractor.


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## adeyo (Jun 6, 2012)

PStechPaul said:


> For maybe about $100 you can get a 2HP AC motor and VFD and use them for a go-cart or tractor.


 Exactly! That's what I was thinking. I have both a go kart without an engine and a riding lawnmower with a blown engine. I really want to learn the AC route because it's something I want to do in the future.... So I was thinking maybe with these old items I might be able to do exactly what you're saying and make a miniversion of an AC automobile. That way I can learn the process and the parts on less-expensive materials. 

Would a 5 hp AC motor work with the 15 hp vfd?

Also, I have an ac-dc 28 volt generator that sounds at 10000 rpm, any creative ideas here?


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## adeyo (Jun 6, 2012)

Spec plate of the generator attached . ...military airplane maybe?


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## PStechPaul (May 1, 2012)

It will be a problem getting the 500-600 VDC for your 440 VAC drive, if it's even working or suitable at all. Better to start with something new or guaranteed, and 240V:
http://www.ebay.com/itm/HIGH-QUALIT...lectrical_Equipment_Tools&hash=item35b7cb9fd0

This may be a good deal as well with higher HP:
http://www.ebay.com/itm/ALLEN-BRADL...367?pt=LH_DefaultDomain_0&hash=item2c672a6bbf

The generator looks intriguing. See if you can spin it and get some voltage out of it. You might be able to use a drill, but it looks like a very powerful machine, 500A at 28V is 14kW.

But if you really want to learn about this stuff you will need to be able to hook up these devices and test them. Once you get something working or obtain the users manual and other goodies we can help fine tune your build, even if it is a 2-5HP gocart or tractor.


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## aeroscott (Jan 5, 2008)

I saw a oil cooled 40kw alternator (aircraft) size of a car alternator , 10,000 rpm .


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