I'm using a Mega 2560 Arduino board and 8 servos, 6 of them are HS-645MG Ultra torque servos. The operating voltage is 4.8-6V and I want to know if the arduino can power all 6 from the 5 V pin and if so what type of power supply should be used in terms of voltage/ amperage ratings. I still need the other 2 servos. It wold have to be strong enough to move 5 lbs attached to a 2 ft pole. I assume i could use the same type of servos for that.
For more info on the servos:
https://www.servocity.com/html/hs-645mg_ultra_torque.html#.ViWrR_mrQTY
want to know if the arduino can power all 6 from the 5 V pin
No, you need an external power supply.
Most servos will run on 4.8 - 6 volts; budget about 1 amp per servo - so for 8 servos, you'd be looking for at least an 8 amp supply; a PC power supply using the 5 volt rail would probably work OK. You can't run these off the 5 volt regulator on the Arduino (in fact, such a setup can easily damage the regulator, if even one servo is used, and it is under load - at best, it will cause the voltage to sag and reset the Arduino). So, as noted, a separate supply is needed. Hook the positive output of the supply to the positive lead of all the servos, negative to negative, and hook the negative to the ground of the Arduino, too. Hook the signal leads to the appropriate digital pins on the Arduino for control, of course.