My amp project power supply has several 120v loads as well as the 240v plate
They include a fan that draws about 100 mA, a screen supply that will take
about 350 mA,
and a filament transformer that will probably draw about 1A.
The problem is how to connect the 120v loads. One solution is to just use a
which will provide a neutral in addition to the two hot wires and ground. Then
loads can be connected between the hot wires and the neutral.
Another option is bridging the 120V loads across the two halves of the 240V
transformer's primary. I've seen this done with fans, etc. The primary acts as
autotransformer to provide half voltage. Then I could use a simple 3-wire
But I wonder how far I can go with this. If I put the filament transformer
across one half
and the screen supply across the other, would the unbalanced currents cause the
the lightly loaded side to be excessive? This is a smallish amplifier -- the
transformer is about 1 kVA.
Has anybody tried this?
No, I am NOT thinking about using the ground as a neutral! If the bridging idea
impractical, I'll bite the bullet and put in a 4-wire circuit.
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