How to find out whether an arduino can control a servo motor I have a servo motor with following specs
Torque - 1.08Nm
Max rpm - 3000
Current rating - 7.8 amp
Max voltage - 56V DC

Please tell me how to calculate whether an arduino board - uno rev 3 can control the servo motor? If not, how to find out how many such boards are required?
An Uno most definitely cannot directly control that motor. According to the specs here,


  They operate at 5 volts. Each pin can provide or receive a maximum of 40 mA


So your motor has needs about ten times the voltage and 200 times the amps that the Uno can supply. Of course, you can always get a driver of some sort for the servo.