So im working on a biped and im using the 5645 hi-tec servos… But every time i turn on my robot (connect it to a power supply) it starts humming, if i lift the robot it stops, also if i take some weight from the robot it stops… is this bad? normal?
Also i have my robot connected to a bench PSU, 6V at a max of 2A… Some times when i send a signal to a servo to move somewhere, the “Shorted” light will come one and my robot will freeze… If i go lift it and force the servo to move to my desire position it will move and the “Shorted” light will go of…
note: im running my servos using a ssc-32 board, with a single power source… i connected my bench PSU to the VL port
I don’t have many Hitec digital servos, but those I have had our Noisy!!! One reason I have shied away from using too many of them. Another reason I don’t like some of them is there is no way to tell them to turn off, except remove power…
The reason your ‘shorted’ light comes on is probably from trying to run over a dozen servos on a power supply that will only supply 2 amps. It’s very possible for a single stalled servo to draw 2 amps by itself. I would suggest getting a bigger power supply.
Ahh, they are different units, actually. The battery is 6V, 2.8ah, or amp-hours. Meaning it can supply 2.8 amps for 1 hour, or 1.4 amps for 2 hours, or any other multiple of current and time that comes out to be 2.8.
Most batteries will display a C value. This value is a multiplier of its capacity that tells you the max amount of current it can supply at a given time. Multiply the C value by the capacity in amp-hours and that is the maximum current it will supply. For example, a 2.8ah battery with a C value of 10 can supply 28 amps max.
You’re correct about the 6 minutes, although I’m not sure if that is actually a 10C battery. I don’t think anyone here has had problems with it so I assume it gets the job done. If the battery doesn’t end up working well I’d suggest getting a lipo battery. They are cheap, light, high capacity and can supply a lot of current.
Your servos probably won’t draw large amounts of current for sustained periods of time. Only in times when there is a lot of load on a certain joint, e.g. you bend the knees and maintain that stance. But even in that case, large current draw will be isolated only to certain servos.
The best way to get an idea of the normal operating current is to hook up an ammeter between the battery and the bot and see what it says while the robot is moving around, and while it’s standing still.
