Power needed to drive 3 nema 42 motors?

I have a bp clone that I'm retrofitting with 3 nema 42 1070 oz-in
motors. They draw 6 amps per phase each. I'm driving them with
Gecko 201 drives. What amperage power supply will I need? Three
motors times 2 phases times 6 amps equals 36 amps! Do I need to
shoot for this size supply? Where do you get a transfomer that size
( 70v, 40a )? Can I uses a variable transformer and a full bridge
recitifier set to approx. 70 volts?

Thanks
Brian