F.E.T burning problem

[saleemkasuri]

Dear friends , i manufacturing ups by self using F.E.T's module ,
i face a problem that mostly in 24 v designed UPS the F.E.T's burned frequently and some time same problem in 12 v designed ups ,
tell me any friend to solve this problem and guide me that this problem why occur ,

 

[Magvitron]

'Burning' will be due to a whole lot of things.. be more specific c, did you designed the thing? If you are willing to share the schematic, please do so. Many members can help if you provide with all the details.