EEVblog Electronics Community Forum

General => General Technical Chat => Topic started by: jonovid on July 31, 2021, 02:48:46 am

Title: earth leakage protection in 240 volt AC inverters
Post by: jonovid on July 31, 2021, 02:48:46 am

I got given a box of old electronics.  :-+ ;D in the box was two cheap input 12volt DC to 240 volt AC output inverters.
the 300watt  type used for camping or outdoors.  not tested then yet.
I am getting second opinion before running one. 
what personnel protection do we have?  is it floating 240 volt AC.  :scared:
before I start poking around inside one.
what is the case here  :-//

Title: Re: earth leakage protection in 240 volt AC inverters
Post by: james_s on July 31, 2021, 03:07:40 am

They're very simple. They consist of a boost converter that generates ~340VDC which feeds an H-bridge that turns it into an AC square wave with dead time, aka "modified sine wave". The battery powering them is itself a floating source so obviously the output of the inverter will be a floating source unless you earth it.

Just plug it in and connect a lightbulb or something to the output to see if it works, they're probably fine. Usually when they do fail the problem is some bad mosfets.