One power supply or 3?

Looking for a bit of clarification. Some of you know I'm beginning
the conversion of a Bridgeport Series I CNC machine to PC based
control operation.

I'm going for reliability and functionality vs. high performance.
I've decided to go with EMC and the Gecko 210's rated at 7A &
80VDC.

I have found some nice toroidal transformers that will yield 9A at
44VAC effectively giving me about 62 Volts. I'm planning on
building 3 seperate power supplies for each axis. They aren't
terribly expensive and I estimate the entire power supply (using
surplus parts) to run less than $100. Yet in my conversations with
Tim G. and heard that one power supply is enough to drive all 3
drives. I'm interested to understand the theory behind this thought.
(not being super techno savvy).

Thanks for all the help guys. Indeed this is a valuable resource for
anyone contemplating such a project or looking for advice.

Marty