On Sat, 18 Sep 2010 04:49:22 -0500, "RogerN"
wrote:


"Karl Townsend" wrote in message
.. .
I'm looking to rectify 240 VAC into DC with 100 amp surge capacity.
This will power the servo amps on my Matsuura bedmill. I probably
won't ask as many questions as Iggy about my winter projectVBG

The largest I found is 50 amp:
http://www.digikey.com/scripts/DkSea...me=641-1381-ND

Do I need to come up with some way to put three in parallel? If I do
this do I need to fuse each rectifier?

If a 100 amp unit is out there, my life would be simpler.

Karl

Mains to DC bus is built into most ACVS inverter drives. If you could find
a large, bad, obsolete drive in the trash you would probably have what you
need to get the DC bus voltage. Note this is going to be over 300V DC, be
careful. I've seen a lot of old model drives in the scrap bin at work,
usually from an upgrade to a newer drive.

Also I think you can use an SCR as a rectifier if you connect the control
lead to the correct end. I'm not sure if you need to use a resistor or not,
thought someone here would know more about this.

So, on your ebay search, rectifiers, diodes, SCR's, and drives (obsolete or
bad to be cheap) could do what you need. Sometimes companies stock power
SCR's for their old drives, as drives are obsoleted, their replacement SCR's
can end up on eBay. The newer drives I've worked with usually have IGBT's.

RogerN

!!!!!!!!!

I got a dead 50 hp. old old VFD in a huge cabinet. Its going to have
all the parts I need. I didn't make the connection till just now.

Thanks Roger

Karl