Hi everyone, I'm getting kinda mad now so please help me before I do something stupid
So basically I just finished assembling my new robot arm recent ordered from eBay, and with everything mounted it's a bit heavy, anyway it's powered by 6 mg996r. I began by testing one of the servos via a 6v battery pack (4 AA), worked but waay to weak, luckily I had a battery pack used for my old rc car. It was rated 7.2V and 2500mah. The voltage matched exactly the maximum voltage input I the servo, so I simply connected everything and tested it out. Suddenly after a few seconds my room looked like a Jamaican apartment with smoke everywhere.
And yes this was with only 1 servo! Everything was connected properly with jumper wires, common gnd etc so why did I fry the servo? Did it eat more amps than it could handle? And the more important question, how do I fix this problem?
Where did you purchase your MG996R servos? I purchased four MG996R servos off ebay and they were junk. They had plastic bushings instead of ball bearings and the servos quickly became hot with mild use. Hopefully the ones you purchased are better than the ones I purchased.
I buy lots of stuff off ebay but I no longer purchase servos from ebay sellers. I purchase most of my servos from HobbyKing.
Thank you for the links, so now I'm standing here with my light wallet wondering what to buy, i can either use a LM2596 per servo, or the step-down module you used for your hexapod, or a UBEC that seemed kinda nice. However, jremington said:
jremington:
To run 6 of them, you will need a 5-6V power supply capable of 10-15 amperes.
It got me thinking why not just buy a ac to dc power supply that offers 5V 20A? Founded this on eBay Click me. Will it work? Just hook up to my wall with 230v? Is there any downsides?
And yes i bought my servos on eBay and i honestly have no idea about their build quality. Haven't had the time to open them up yet.
jremington:
If the eBay power supply works according to specs, it should be fine.
Agreed.
I have had trouble powering motors from AC to DC power supplies. I think there's something about the inductive nature of the load which cause trouble for some power supplies. Hopefully this won't be an issue for you.
Its the heavy current draw from a supply with an over-current cutout circuit that's the issue.
For a motor you either have to provide all the stall current, or droop the voltage on overload.
Having an active cut-out circuit is only approriate if the supply can provide all the stall current
without overloading. A simple current-limited supply (like a bench power supply) is a good
approach. Computer supplies are not designed for motors. Sometimes a hefty capacitor bank
can rescue the situation, but that can also interact with the over-current cutout!