Greetings.
I have to build a robotic arm, which needs 3 MG 995 servo motors and 2 sg90 servo motors.
I have seen on the Internet for them to work properly the power supplied by the Arduino board is not enough.
For this reason I have to buy an external power supply. The problem now is to calculate how much current
must be able to supply this power supply for the correct functioning of the servo motors. A power supply is used in a video
5V, and a current of 10A, which seems a bit excessive to me.
Servo mg995:
-Weight: 55 g
• Dimension: 40.7 x 19.7 x 42.9 mm approx.
• Stall torque: 8.5 kgf·cm (4.8 V ), 10 kgf·cm (6 V)
• Operating speed: 0.2 s/60º (4.8 V), 0.16 s/60º (6 V)
• Operating voltage: 4.8 V a 7.2 V
• Dead band width: 5 µs
• Stable and shock proof double ball bearing design
• Temperature range: 0 ºC – 55 ºC
Servo sg90:
Weight: 9 g
• Dimension: 22.2 x 11.8 x 31 mm approx.
• Stall torque: 1.8 kgf·cm
• Operating speed: 0.1 s/60 degree
• Operating voltage: 4.8 V (~5V)
• Dead band width: 10 µs
• Temperature range: 0 ºC – 55 ºC
Please can you tell me how can I calculate the correct current.
Thank you.
Those datasheets are likely made by sales people. Not Your fault. They lacks the parameter: "Stall current" so I have no help for You. Using an oscilloscope measuring it is possible but likely there are other helpers having experience of those servos.
Bingo. Well done! That's the data needed.
That's the mg995. Multiply the stall current by the number of those servos. Do the same for the other servo and add the figures.
Good Catch! You know "An Arduino A Power Supply it Is NOT!" That catch will probably save you the cost of several Arduino replacements and space in the trash bin.