[Elecraft] OT: Transformer windings, colour code?

Sat Dec 21 15:13:07 2002

Hi Julian,

You can put a low power 240V light bulb in series with the primary power
line. This will limit the current to a safe level.  Connect the primary
leads in series one way (say, white to black connected together and power
applied to brown and pink with the light bulb in series), apply power and
observe the bulb brightness. Connect the leads the other way (white to pink)
and see how bright the bulb is. The  connection that gives the DIMMER result
is the correct phasing for the series connection.

For the secondary, connect two leads together and measure the voltage
between the other two leads, if its zero, you can connect them for a
parallel connection. If the potential is not essentially zero, there may be
a problem with parallel operation. Watch for excessive transformer heating
even with no load. Run it with the secondary windings unconnected for 30
minutes to an hour and see now warm it is. Then connect the secondary
windings in parallel and see if it gets much warmer.

73/ Bob -  AG5Q

----- Original Message -----
From: "Julian (G4ILO)" <[email protected]>
To: "Elecraft List" <[email protected]>
Sent: Saturday, December 21, 2002 11:56 AM
Subject: [Elecraft] OT: Transformer windings, colour code?

> I was all set to wire up my new power supply for my K2 when I hit a snag.
I
> don't know which windings to connect together to put the primaries in
> series (for 240V) and the secondaries in parallel. The only information
> provided is on the transformer itself, which says:
>
> Primary 2 x 115V Brown - White Black - Pink.
>
> Secondary 2 x 18V Red - Yellow Blue - Gray.
>
> I can't find any technical info on the manufacturer's website, except that
> it complies with the latest European standards. Is there a standard colour
> coding for transformers? Alternatively is there a safe way to find out
> which winding to connect to which using a meter? I'm afraid that if I
> connect them the wrong way round, out of phase, the thing may go up in
> smoke.
>
> 73,
> --
> Julian, G4ILO. (K2 #392)
> Homepage: http://www.qsl.net/g4ilo
>
>
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