Australia
Asked — Edited

Servo Power Source Questions

Hi,

My first question is about whether or not its fine with 24 servos to twist all the red wires together and all the black wires together so you end up with 26 wires - 24 data + 2 power. I will use a 7.5V46A power supply to provide power to the servos. The data lines will hook into my EZBV4 Microprocessor. It seems like the obvious answer is 'of course you can - each servo will suck current as required up to a total of 46 Amps'. But I noticed some major jitter on OTHER servos when I tried this in a very messy way with bad wiring. If my wiring is good, will there be no problem? I mean, power won't divert the wrong way if the 24-way splitter is made well, right? I imagine that without a pulse signal from the data line, there is a steady low current flowing through an idle servo. And then I guess the pulse from the microcontroller simply tells the servo how many electrons it needs at any given moment... But does the current move in a different direction when the pulse tells the servo to turn in the other direction? With 24 servos rotating in thousands of directions each hour, this last question would mean that the servos can't all simply plug into a transformer/battery using a single input. I hope this is not the case, but if I need some kind of power management system (rather than a fat wired splitter to handle all those electrons), I need to know. Anyone using lots of servos at the same time (more than 20A)? Thanks.


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#1  

It's not clear...

did you connect 24 servos to an EZB (no more ports available) and the servo's power cables to an external power source.

where you experienced the jitter ?

#2  

If you are powering the servos separately from the EZ-B, then you'll need a common ground, but yes, one ground to the EZ-B along with the 24 signal wires, then one power and common ground to all the servos will work.

Alan

Australia
#3  

The transformer is AC240V from the wall socket to DC7.5V output. It has + and - (red and black). Live and Ground, I think. The data will come from the EZBV4.

When I ran my little experiment I was using four Hitec 645MG servos with a 4 servo controller, not the EZBV4. The wires were probably getting pinched and / or were not connected at each point properly to each side of the 13 pin trailer connector I was using. I just ordered a few 9380TH servos. These will be digital. I'm hoping the jitter was caused by my bad / pinched wiring and not some kind of earthing or wire-sharing problem.

#4  

How many amps does the power supply put out? It is possible to only put out a few amps which will starve the servos and cause the jitter.

Sorry, I now see 46Amps.

Should be good for about 15 or so servos if they are not all starting to move at the same time. I would assume you are actually going to get about 35 amps from this as they are often over rated.