Hi,
Sometime lurker, first time poster here. I am a mech eng by training, so know just enough about electricity to be a danger to myself and others
. I've had a look at other posts but haven't found the exact answer to my specific situation so will start a new thread.
I recently bought a "Migbot" 3D printer kit (
https://www.3dprintersonlinestore.com/migbot-prusa-i3-kit), and am in the process of putting it together. I am generally happy with the quality of the build, but have read of a few problems on other forums so am proceeding cautiously. So far the biggest problems I have heard of are:
1) Someone getting "zapped" when touching the power supply case.
2) Someone frying their controller board when using the supplied PSU.
3) The PSU being under-rated for the kit and not being able to supply enough power.
I would like to avoid burning down my house or blowing up the printer (not to mention avoiding electrocution), so I thought I would run some checks before I hook up the power.
Problem 1:
The PSU I have is a no-name unit made in China, maybe a switchmode power supply (see photos)? The details on the other person's problem were sketchy, but from my limited understanding someone should only get a zap if there is a fault AND the case is inadequately earthed. Is that correct? I have checked the resistance and continuity between each of the power terminals and the case with a DMM, and found only the earth terminal is connected (0 ohm resistance/continuity buzzer went off), so if I wire up to an Australian power lead (live, neutral and earth) I presume it should be OK (even if it develops a fault later)? I plan to run it from an overload-protected power board as well.
Problem 2:
The controller board is a "MKS Base" v1.3 similar to the one shown here:
http://reprap.org/wiki/MKS_BASE. Unfortunately it is not open-source so the information on it is a bit sketchy. Similarly the details of how the person fried their board aren't exactly clear. Aside from reverse polarity issues, and assuming there are no manufacturing faults with the board, do I need to be concerned that the PSU could damage the board? If people are finding the psu under-rated, then I presume over-current shouldn't be an issue. Is an over-voltage something to be concerned about?
Problem 3:
I'll check this once I have the printer hooked up.
Thanks for any advice you can offer,
Michael