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Topic: Need Advice: Powering variable number of servos with a dedicated voltage rail (Read 393 times) previous topic - next topic

Sheldon

I am building a  stationary robotic arm, probably with a stepper motor base and servo joints. I haven't finalized a design, but I will probably be using Microrax extruded aluminum and "like" 4 servos. My main concern at this point is providing adequate power to my system. I am currently looking at a bench linear power supply that can be viewed at the link below.

http://www.hobbyking.com/hobbyking/store/__6222__Towerpro_MG946R_12kg_55g_12kg_20sec.html

My main question is: Can I establish a dedicated voltage rail with the supply that each servo (and stepper) connects to. In addition, is there a method of calculating/modeling the voltage/current settings for the power supply to ensure the necessary amount of power is being transferred to each motor. I would really like to learn a modeling method for future reference. On a side tangent, I haven't decided on controller hardware (Microcontroller, and stepper motor driver/h-bridge system) if anyone has a good suggestion please share.

johnwasser

You have to set the voltage to somewhere in the 4.8 to 7.2V range the servos are designed for.  The current has to be set high enough for the sum of the servo currents.  Typically 1A per servo is the figure I've seen.
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Sheldon

A buddy of mine confirmed what you stated. He also said that if you get some slightly more hefty servos (load capacity) you can get away with powering them with lower currents. I ended up getting a slightly bigger supply that could handle 5A, I'll post the results of my experimentation with it here in this thread.

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