# What should be the required operating voltage for Servo motors in my 5 DOF robotic arm, with 50 kg payload

These are the estimated torque values of all axis in our applications 1st Axis- 226.57 oz-in - 478oz-in 2nd Axis- 756 oz-in -1590oz-in 3rd Axis- 356 oz-in - 749.7 oz-in 4th Axis- 188 oz-in - 395 oz-inch 5th Axis-17.7oz-in - 37.2 oz-inches Robot arm has to lift payload of 50 kg, I want to source servo motors , for selection I am confused what operating voltage for servo motors would be suitable,DC or Ac and how much in Dc

• Ah, let me see. Usually hobbyist grade servos use 5V to 6V. More serious applications use 7V to 12V. You can search "servo", "10kg", "50kg" to find any servo that meets your spec. You might also like to search "digital servo" to find heavy duty servos. Sep 25, 2020 at 9:52
• if we use Ac servos, would 400 v be convenient? Sep 26, 2020 at 4:50
• Ah, let see. 2000 oz-in = 144 kg-cm, and 150kg is the typical limit of 12V digital DC servo . Of course you can custom make bigger torques. For AC servos, you can easily find biggere torques over 200kg. It also depends on your torque/speed trade offs. And digital servo can have very fine position control, up to 2048 steps per revolution. AC servos can only do very coarse spec. Also you need to consider weight and space requirement. Again, google is your friend. Cheers. Sep 26, 2020 at 5:37
• yes,you are right, Thank you so much Sep 26, 2020 at 13:02
• Torque and force is controlled by current and gear ratios. Power is determined by acceleration of load. Voltage is only a factor when current gets large (e.g. :>10A) Does it move fast? Define your problem with torque and angular mass to compute angular force with mass and acceleration by design limits for starting and stopping. Then angular speed and momentum p=mv, F=ma and current/torque to reach that speed. These computations must be done before voltage and AC or DC are considered because acceleration of mass determines torque Oct 1, 2020 at 20:34