I purchased an 800 va luminous invert-er from a local luminous dealer 3 months ago. It seems to work fine most of the time. But it makes a humming noise. I am not sure whether it is a Square wave invert-er or a Sine wave. I wanted a sine wave and the dealer has installed it saying it is a Sine wave. However when I searched over the internet regarding this I found out square wave makes noise and Sine wave ones are very quite. The ceiling fan when on invert-er runs slower making more noise than usual, when there is power.Is there a way I can check with its model or something to find out the type. The luminous site doesn’t have any info on this. I want to find out if the dealer has cheated as square wave ones are cheaper or worse has installed a duplicate equipment. Can you guys please help?Also the invert-er today has been working on invert-er mode even when there is power at home. Any solutions?