Servo motor power consumption issue

Question

I am using servo motor model no. MG995 with Arduino. I don't know the current it consumes while powered on and while lifting a 10 kg of weight. I am currently using a 5 V, 1 A power supply with one motor but in future I need to connect 6 motors to single supply.

Answer 1

Firstly consider the servo torque limitations, if loading increase from specified limit the it start stalling and even can gear get fail and burn servo itself, possibly.

And another concern is with power supply. You are using metalgear servo with power supply of just 1 A. As per the specification provided by greenonline (in previous answer), the servo needs 1.2 A at stall condition. You require higher ampere power supply. Your setup will work with ideal no load condition but not on loaded condition.

You should not power servo directly form the Arduino. You should design the driver circuit or board for power supply and common both ground of the Arduino board and driver circuit.

And it is recommended that you should use multiple power supply and divide the power supply to the group of servos. It will help in stabilizing your working and power. High ampere drawn by one servo does not affect the other of power supply is separated.

If you have higher power supply system in which you can control the voltage and ampere both then you can go for single supply also. Considering 1.2 A stall current and all 6 servo are same then you should supply 1.2×6 = 7.2 A for working without any problem.

Answer 2

From the TowerPro website from the MG995:

Specification:

• Weight: 55 g
• Dimension: 40.7×19.7×42.9 mm
• Stall torque: 9.4 kg/cm (4.8v); 11 kg/cm (6 V)
• Operating speed: 0.20 sec/60° (4.8 V); 0.16 sec/60° (6.0 V)
• Operating voltage: 4.8~ 6.6 V
• Gear Type: Metal gear
• Temperature range: 0- 55 °C
• Dead band width: 1 µs
• servo wire length: 32 cm
• Current draw at idle 10 mA
• No load operating current draw 170 mA
• Stall current draw 1200 mA

From the stall torque at 6 V it can lift a maximum of 11 kg at 1 cm from the axis of the servo, so your load of 10 kg would be on the limit. THe MG995 may not be sufficient.

Also, as the stall current of one servo is 1200 mA you probably need a bigger power supply, or rather one that is capable of supplying more current.

Even with no load, six servos, when operating, will consume (6 x 0.17 =) 1.02 A, so again you will need a bigger supply.

The MG996R has a similar specification:

Specification:

• Weight: 55 g
• Dimension: 40.7×19.7×42.9 mm
• Stall torque: 9.4 kg/cm (4.8 V); 11 kg/cm (6.0 V)
• Operating speed: 0.19 sec/60° (4.8 V); 0.15 sec/60° (6.0 V)
• Operating voltage: 4.8~ 6.6 V
• Gear Type: Metal gear
• Temperature range: 0- 55 °C
• Servo Plug: JR (Fits JR and Futaba)
• Dead band width: 1 µs
• Servo wire length: 32 cm
• Current draw at idle 10 mA
• No load operating current draw 170 mA
• Stall current draw 1400 mA

So you probably need to rethink your choice of servo.