servo amps, power supplies; addl endearments

Alan, Jon et al thanks for your thoughful replies to my previous post
re servo amps and power supplies.

After reading the docs for the Baldor UM4-100 amps-in-a-cage I've
got, I'm starting to think that the power supply for the axes motors
is built-in. i) The chassis has a transformer and cap each of which
are half-beer can sized (12 oz, not a Foster's), ii) the specs call
out "rated bus input nominal 70-105 VAC" and "nominal output voltage
100 VDC", iii) the chassis connections diagram shows "isolated AC
input power 70/105 VAC," "logic and fan power 115 VAC," and black (-)
and red (+) wires heading out to the motors, and iv) the catalog
says, "The chassis includes the power supply, over voltage protector,
and associated hardware," and finally v) poring over the docs for the
terminal block doesn't reveal anything like "100 VDC in." I guess one
way to find out will be to connect the thing to a motor and see if
spins. Before doing that, however, I'd like to find out what an
isolation transformer is.

The "typical connections" diagram for the individual amp cards shows
a tachometer with two leads going to + and - tach terminals, plus
limit switches and interlock/reset, and something called "motion
controller +/- 10 VDC signal" with leads going to "differential"
and "signal input" terminals. So, what is "motion controller"? This
sounds suspiciously like the brains of the operation, so I assume
it's the soon to be released servo card Jon is working on.

Where do the rotary encoders fit into this scheme? Do the encoder
outputs run to the PC-servo card and that card sends output to the
motion controller terminals on each amp card? Or are the encoders
themselves the so-called motion controllers and there's another type
of connection between the PC-servo card and the amps?

What is the relationship between the nameplate voltage on the amp and
that on the servo motors. If "bus voltage" is 100 VDC does that mean
I'm hunting for 100 VDC servos. I do understand that the continuous
wattage rating of the motors should not exceed that of the
amplifier. Whether the amplifier's ratings (100 VDC 6/15 AMPS
cont/peak) is for _each_ motor or all three (or four) only the
technical writers at Baldor know for sure.

Lastly, I've checked through the archives, but can someone suggest a
source for Bport-sized PMDC servos w/ tach? Maybe some high stepper
has a redundant pair for sale?

As always, thanks very much for the carefull considerations my
questions have gotten on this group.

--Jack W.