Hi all, I have built an electronics enclosure for my CNC router, incorporating a estop circuit and relays for dust extraction and spindle coolant pump (24vdc & 240v ac circuits). But I’m finding some stray voltages in lines where there shouldn’t be. I have created a schematic of what I’ve built, and was wondering if someone might be able cast their eyes over it and see if I’m missing something? Note, I’m based in the UK (ie. 240v) Many thanks in advance...
Peter, An example is when the contractors are energised, 240v ac is present when I test the 24v dc black box psu line to Earth.
Yikes! Power off now! Step 1) Remove the expensive electronics from the case until you fixed the issue (warranty won't cover that kind of damage, I think) Step 2) Isolate the source of the short - thats not induced, its a short of some sort - seeing as it gets to the 24v line, I'd start by removing mains supply from the 24v PSU and seeing if it goes away. Continue onward if it doesnt until you find what does. Would have been easy if each section had its own breaker in a Distribution fashion (;
Yeah, ‘stray voltage’ was a bit of an understatement ;D good idea about omitting the 24v PSU for troubleshooting. I’ll pick this up tomorrow and post any results.
I pulled it to pieces today, testing every element. Turns out the plugable relay module for the coolant/dust extractor circuit was essentially single throw. So it was combining the two voltages at the common contacts. *face palm* Otherwise, the schematic works as expected.
That could have ended very badly. Glad you caught that. It's also a good lesson, different electronic components can often look the same but function very differently, know exactly what you are getting.
