gwes wrote:
Here's a money-grubbing question from a hard-case tinkerer:

Leadin:
In order to run a 3-phase motor drive from single phase input,
the user must derate the unit by 50%. This is because the input
rectifier and filter capacitors are too small to handle the increased
peak current of a single phase feed.
You need to consider that many hobby-garage shop types buy used
VFDs on eBay for a fraction of new cost. The cost to them of
derating the drive is quite small. I've been running a 1 Hp
Bridgeport from a 1 Hp-rated, 3-phase-only Magnetek drive for
years, because I didn't know any better when I bought it. It
has not had any problems at all, and runs cool. When all this
stuff about derating the drive came out, I looked up the power
module in it, and it has rectifiers rated at 30 A continuous.
As a 1 Hp drive, it shouldn't draw more than about 4 A RMS.
Given the worse power factor for a single-phase input, I'm
guessing the peaks may be around 10 A at full load. I had to
put a line filter in the input to keep it from trashing some
equipment in the shop, that probably helps limit the peak I.
So, the rectifiers look like they are more than adequate for the
job. If the capacitors ever croak, I can replace them, although
the whole bank could get expensive.

You have to remember that these units are designed to run in
enclosed cabinets at 50C ambient for 10 years continuously,
sometimes with a motor start every minute. That is so much more
severe than what most hobby-garage shop users put it through.

Jon