I have bought su-kam 650va shiny pure sine wave inverter on sep-2014. After installation, I have noticed Buzzing sound from inverter.
The customer care technician told that it’s normal for pure sine wave inverters. But now all ceiling fans give loud sound in Backup mode, CFL & LED bulbs fused. Each and every corner of building is so noisy like a jungle in backup mode. I really feels unhappy with this product. SO DON’T BUY SU-KAM PRODUCTS.