Unipolar Motors, Power Supply, and 3 Axis Controller

[Nightwork]

I have 3 150 oz-in unipolar stepper motors. On the side of the motor is list Volts 2.3 and Amps 4.6. Now I working on the hardware to control them. I have found a very nice chip to control them, however I have several questions. Here is a link to the data sheet for the chip.

http://www.jameco.com/Jameco/Products/ProdDS/141532.pdf

1.) I have heard something about using a higher voltage when powering motors. Can anyone explain this to me?

2.) The chip can not handle the current I need, so I plan on using MOSFETs. Can anyone point me in the direction of a schematic that will show how to use them? Also is there any other issues?

3.) What voltage and current power supply should I buy? Currently I looking at a 3volt 15amp.

Nightwork

[mardus]

You can find answers on this thread:

unipolar motor microstepping

1. For usefull motor speeds you must have PS at 10 - 20 X rated Voltage, but keep rated motor current.
2. Track a.m. Thread.
3. I will take 36V 10A P.S.