What is the suggested way to connect the odrive to power? With a barrel connector to a switching powersupply I get sparking at 36V.
I now integrated a switch that limits the inrush current by using a 200 Ohm resistor. The switches might have some bounce…
Here is a badly drawn schematic of my setup (sorry), the switches at the power supply are the barrel connector. Power on sequence is: open switches, connect barrel connector, close 200 ohm switch, close normal switch and reverse for power down.
Great question!
What you drew there is a pretty textbook precharge circuit – I run something similar to that on my desk. There’s also products that do this specifically (sometimes called antispark switches), as well as connectors with integrated precharge resistor. One other option that I frequently use is to just only connect the power supply to wall power once everything is wired up, so that only the AC power is being physically switched.
Thanks, I was a bit worried that Im doing something wrong, since after changing to this setup on the very first power on one of the odrives didnt boot. Got a little scared there. Is this unrelated or is the resistance too high or can bounce in the switch cause problems?
If you’re doing the proper precharge → main switch sequence, then bounce shouldn’t matter as much. I usually recommend having some sort of relay/contactor though instead of a physical switch, if possible, just for current/voltage capacitity
Hmm there is definitely something wrong. Switched to a 120 ohm resistor and now both odrives did not boot properly (not reachable on uart and usb). I sadly dont have an oscilloscope here to look at the voltage.
Hmm – I’d double check the resistor, unless it’s pulse rated, it would be easy to burn it out doing precharge like that. I’d probably recommend something chunky/wirewound – something like this.
However, does the ODrive not boot even with only USB connected?
I was able to borrow an oscilloscope.
The 120 Ohm resistor was rated for 3W, so probably not the issue. Here is the voltage directly after the switch:
