Transformer windings. Do they have a polarity?

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Sammas

Well-known member
Joined
Sep 30, 2004
Messages
547
Location
Sydney, Australia.
I have a silverface fender champ that needs to be wired for 240v (current 120v).

It has dual windings on the primary and they were wired in parallel (ie. one end of
each winding when to the mains neutral, while the other ends went to the mains
switch).

Regarding wiring these two windings in series, does polarity play into it at all? I
have no documentation on the transformer at all. I am suspecting the answer to
my question is no. I have determined which wires correspond to which windings just
by testing for continuity (disconnected from the neutral and switch obviously).

Just grab one wire off the switch, and connect it to the wire off the mains neutral from
the OTHER mains winding...

IE: We should be seeing continuity between the switch and where these two winds were
joined, and between this join and the mains neutral?


Piece of piss right? Wiring Toriodial's has corroded my decision making as the label has
everything so elegantly laid out!


 
Sammas,
The windings definitely have a polarity; you need to connect them properly or you'll get
no output from the secondary windings (plus I'm sure it's not good for the transformer  :( )

Check here on the web: www.schematicheaven.com/fender.htm
Find something similar to what you have and follow along....

JP
 
I've been searching for a schem, but most only appear to have 110v wiring with no reference to any dual primary windings.

As far as polarity goes though, at 110v the two windings are in parallel. For names sake, that makes the ends connected to
the switch 110v, and the ends connected to the mains neutral 0v. As long as I connect one 110v end of one winding to the
0v end of the opposing winding we'll get the two in series for 240v operation.

Correct?
 
Yes.
If you know how the 120V version was wired, the 2 wires that were originally tied together
and to the switch can be called the "Hot" side of those windings (just a name).
The other 2 wires that were tied to the AC Neutral can be called "Cold".
For 240V operation, one winding's HOT lead goes to the switch, that winding's COLD lead
goes to the other winding's HOT lead (and nowhere else). The remaining COLD lead goes to AC Neutral.
You've created a single (series-connected) primary winding by doing this.
The overall "polarity" of this (complete) primary winding doesn't matter ref to which end goes to the switch
or which end goes to AC Neutral. The important issue was the relative polarity of those 2 primary windings
and getting them properly hooked-up together.

You should also change the fuse; you only need half the current now.

What are the colors of the primary winding leads you have? I may be able to find a matching schemo.

JP

 

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