I think 52.5 volts is max you can run in that type connection. Your 48VDC sounds appropriate on the volt side.
Optimally an 18 amp PS should be used, but you can get away with less. I wouldn't go any lower than 12A though.
I would use the proper current set resistors to even the amps out as well. If you have a heavy head or gantry, then this would need more amps. If some axes are made of different components, then the ones that move the easiest would need fewer amps.
Here is a link to the specs on one set of my motors.
http://www.kelinginc.net/KL23H286-20-8B.pdf
You can see that amps and voltage needs are dependent on how it is wired up. You can use your spec sheet to help determine what size supply you need or can afford or how you can wire it to get the max from the supply you have.