STEPPER MTR VOLTAGE SUPPLY HELP!!!

Hi, I'm retrofitting an old BANDIT 3 axis controller with a PC and
master5 software. I've got a 4 axis 10 amp board rated at 50 volts
and I'm grappling with a power supply. My steppers(slo-syn) are rated
at 3.6 volts/6 amps (X and Y) 2.9 volts/9 amps(Y). The manufacturer
of the board staunchly opposes the use of a power supply for the
motors that exceeds their rating due to the board being a non-chopper
style circuit. They are afraid I will fry the motors with a higher
voltage. Although, I checked the voltage supply to the motors with
the old BANDIT and it read 10 volts on X and Y and 30 volts on Z. I
did some testing today and pulled an old power supply out of the old
control that powered the front console rated at 3voltsDC at 3 amps. I
tried that to just test it out and the motors will hardly move the
table. Ive researched this extensively and it seems there are alot of
different opinions on this subject from dont exceed rated voltage to
go at least 20 times the rated voltage. I dont want to go and buy a
power supply thats too small and I dont want to fry anything. Will
someone please help me with this.