Re: [CAD_CAM_EDM_DRO] VFD

I think $10k is a bit high, by about 1.5 orders of magnitude. I bought
Analog Devices ADMC401 dev kit for about $350, and a 15A 1200V PowerEx
Intelemod 3 phase module. The module and supporting power supply, and opto
couplers was around $150. Ended up buying a 50A version, same pinout,
brand new on Ebay for $15. Even though I managed to turn on all 6
transistors at once (inverted logic, in my head...) the Intelemod module
protected itself. I have not burned out any transistors to date.

With about 50 hours of messing around, and just implementing the app.
notes, I got a 3 HP 3 Ph. induction motor spinning. Trying to modify the
app note software, well, has been an adventure (poor dev. tools).

Granted, my goal was not to make a VFD for milling purposes, but to develop
a high power drive train for electric vehicle racing.

So while it is possible to make your own VFD, it is unlikely going to be
cheaper than buying a brand new one from ebay, and it's likely going to
take a lot of time. Especially if you have to ask what's involved in
building one. Kind of like building your own mill from scratch. If you
have to ask what's involved in doing so, then there is a lot you don't
know. And given the price of used iron, it's not likely going to be
cheaper, either. But if your goal is to have a home made bridgeport clone,
despite the time and $ cost, then go for it!

- Steven Ciciora

P.S. a good source of cheap FETs, 200V low ESR caps and fast rectifier
diodes to blow up is used AT and ATX power supplies. A local used computer
store found out how expensive it was to dispose of old computer equipment,
so they advertised an 'all free' sale. I picked up about 30 identical
power supplies for free.

>
>Do you have about US $10,000 to invest in power transistors? Especially
>if you will be using IGBTs, you will need a great deal of care to get it to
>work without blowing transistors.
>
>Jon