I purchased luminous LB LX 875VA INVERTER three years ago from Silchar. It started distutbing from the vary fast day it was installed in my house. I heard some sparking noise from it and then all of a sudden my entire house became dark. All lights, fan got off. I immidiately called the shop from where I purchased it then they called the service engineer then the service engineer told that there may be some manufacturing defect in it. He opened up my inverter and then replaced some parts and then inverter was working fine. Years passed and its efficiency degraded gradually. It makes a very vigorous noise when there is power cut. It is not the beep which every inverter gives on power cut. Beep is there but at the time of power cut it produces a sound which I do not feel to be ok