Power supplys, encoders, servos, techometers and screws

I have a few questions I'd like to ask.

1.) Can any of you recommend a place for regulated power supplies for quite large servos? 2-3n/m constant and 6-7n/m peak. Infact, thinking about it, if servos this size where to all (4) run at peak I could use a few arc welders! I found the peak of servos this size (5.3 amps at 320vdc) to be 1696 watts, that's only a few hundred off my welder and that's for ONE. I guess you have to be careful with the wiring? :)

2.) How do encoders 'work out' (Visualise) the movement of the actual rotor? I've heard the encoders measuring lines, does that mean the encoder sees a load of lines moving out from the inside out making segments (Like a spiders web without the spiral) that it detects in? What exactly does quadrant encoder mean? Just that it measures quadrants made by the lines? I've heard of three different types of encoder, I don't remember their names though.

3.) This will sound stupid probably but are all higher torque servo's higher voltages? The higher torque ones I've found at Pacific Scientific use 320vdc at a few amps when under peak load. But that doesn't make sense, don't the Gecko's control up to 15 amps at 80vdc? If they can control these currents does that mean somewhere sells high amperage, low voltage, high torque motors or is it just a huge safety gap? I don't even want to ask how much a controller from Pacific Scientific would cost.

4.) I understand the encoders are the feedback from the servos to make the system closed and to keep the system aware of errors but tachometers? Is that to take some pressure off the controls, to have a physical piece of hardware measure the rotor's speed rather than to have the software count the pulses from the encoder?

5.) I spoke to someone who distributes for AHHA! who told me the servo's in their Bridgeport deal where selected because of the screws pitch, that being .200". Do most Bridgeport style mills use this pitch or are there lots? Surely it also has something to do with the weight of the table that's being moved on that pitch?

6.) Q: What sort of pet do you find on the floor?

A: t.e.p.r.a.c A <---- Backwards

Thanks for any help at all, sorry there are so many questions,
John


[Non-text portions of this message have been removed]