AC Transformer failure Trace SW4024
I have had two AC transformers fail over the last 15 years in my Trace/Xantrex SW4024 and I would like some opinions or theories as to why this happened. I realize things don't last forever but want to see if anything we do is contributing to the issue. First time grid was down for 3 days, we used power for heat and refrigeration sparingly. When the grid came up everything looked fine, inverter went to bulk to charge batteries. Then after a few minutes the fans came on and a fire erupted from the transformer, luckily I was there and shut it down quickly. Second time, just last week, grid was down for for several hours but the wife did not realize it and did her normal morning routine, hair dryer and curling iron, so used quite a bit of power. When we found the grid down we cut power usage and battery bank came back up to about 25 volts. After about a 12 hour outage the grid came back up, inverter went into bulk charge as normal then after a few minutes the fans came on and the coil smoked. I got to it before it burst into flames and shut everything down. Anybody have any ideas as to why this would happen? We have had grid outages in the several hours range many times and everything came back up normally. Could the excessive use of power been a factor? Hair dryer, curling iron, etc. this time and heat and refrigeration for days in the first scenario.