Why you stick with 277 volts, for your application voltage is not critical, try 240 V.
Your ballasts 50W can deliver only 150mA of high voltage, I think you need much more.
Low resistance is causing overloading the ballasts and drop 277V mayby to 100V
Microwave transformer is a 1000W
trip my breaker every two minutes = a lot of current you taking from transformer perhaps 2000W - 15A breakers ?