In the US you may have better luck finding a GE ECM furnace motor.
The GE ECM is about the same idea, and in warmer regions the sellimg price is a 12-pack. In cooler regions they are more rare.
For the GE ECM, remove the back half (the 'brain'), the 3 power wires from the brain to the motor are already connected star. Just rectify.
The aluminium back half where the brain was would make a decent place and heat sink for the rectifiers. Or it can be left off.
As simple as it gets.
Good news is the brains are getting old and failing.
Bad news is GE now makes a replacement brain.
The power can increased quite a bit with some internal wiring changes. Jerry told how he was doing it.
Stop at the Carrier dealer, admit to being a little crazy, and ask nice if they could save "one or 2 of those real expensive variable speed motors with the brain that goes bad, for an experiment". Don't confuse them with terms like 'ECM' or 'PMA'. Try not to sound like a dumpster diver... the furnace guys don't like (as in HATE) them around here.
G-
