Which fuse to use...???

[acorkos]

What mains fuse rating should I use with a power transformer having the following specs:

Secondary: 300-0-300 V, 150 mA
Filament winding 1: 5 V, 3 A CT
Filament winding 2: 6.3 V, 5 A CT

Thanks for your help

[tubeswell]

Originally Posted by acorkos

What mains fuse rating should I use with a power transformer having the following specs:

Secondary: 300-0-300 V, 150 mA
Filament winding 1: 5 V, 3 A CT
Filament winding 2: 6.3 V, 5 A CT

300v x 150ma = 45va
6.3v x 5a = 31.5va
5v x 3a = 15va
91.5 va altogether

91.5va / 110v = 0.83a

Match to 1A and multiply by two = 2A mains fuse



or if you are on a 240VAC mains

(91.5va/240V = 0.38a) x 2 ~ 1A mains fuse

That PT is ideal for a 5G9 BTW. What were you planning to build?

[acorkos]

Originally Posted by tubeswell

That PT is ideal for a 5G9 BTW. What were you planning to build?

5D4