Safety glasses are not just for mechanics



This week's monster creation: I've built a portable power supply for Rocky. We've designed the robot to hotswap between power from onboard batteries or from a tether, and this is the base of the tether. This lovely contraption converts 2000W of AC to DC, providing 40A at 50V, all within a portable case. If you look closely at the top right corner, you might notice that some of the wires are disconnected. Not just disconnected, but a little bit blackened. That is what happens when you fail to consider startup current. The DC side of the supply is designed for <40A and the bridge rectifier I used was rated for 60A, but the startup current required to charge the filter capacitor was probably several times that. I didn't consider that and the rectifier blew up instantly. Safety glasses are not just for mechanics. So, I've added in an inrush limiter (thermistor) to keep startup current under 40A and I'll be buying a higher capacity rectifier, just in case.
Next step: batteries.

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