Q regarding PT primary voltages

[RobBozic]

Hi,
I’ve got a 5E3 PT with 384-0-384 ac on the secondary. As I’m in Australia we use 240V.


Now on the PT primary I ground the ‘0’ and use the ‘240’, what if I ground the ‘110’ and still use the ‘240’, would I get a secondary voltage of 274-0-274? (384 - 110)


Thanks
Rob

[sluckey]

You'll get about 700-0-700 until the primary winding burns open. Shouldn't take too long.

[pdf64]

...Now on the PT primary I ground the ‘0’ ...

Yikes, no!
One end of the primary connects to the mains 'neutral', the other connects to mains 'live / hot', the latter via fuse and 'power' switch.

[RobBozic]

Yes, I meant wiring the ‘0’ to the Neutral 


It’s for an existing amp which does work.


Rob

[PRR]

What Sluckey said. You would be putting 240V into 240V-110V or 130V worth of primary winding.

First thing: it sucks BIG current because the over-voltage saturates the core and current gets to 10X to 1000X normal.

Next thing: the secondary *rises* to like 709-0-709. Opposite of what you are thinking. Far too much for any g-amp.

Third thing: room fills with smoke as the over-current primary catches fire. You have turned a working PT into a stinky paperweight. (In an extreme case the cellar fuse *may* blow first; actually you should have a proper chassis-fuse which may die faster than the PT.)

You also mess with the 6.3V winding (11.6V) but I don't think it will live long enough to matter.

[RobBozic]

Noted, and Thanks for the reply.
Rob