How should I connect an old tube transformer

[mdr30]

Haven't worked with an old transformer like this and need some help to connect it, maybe from German readers.
Primary is easy enough, 8 and 5 for 230V (and a jumper between 7 and 6), but secondaries escape me. As an example it says:
11 . 12 . 13 2x240V (Doppelweg gleichrichtg.)

How should 11, 12, and 13 be connected? And what does this mean:
"Anodenmitte (12) an Masse legen"?

Looking forward to be enlightened!

 

[petertub]

Ahh, those old elfa transformers !
the secondary is adjutable, note that the midpoint (12) is used in all combination and that the outer pointe are moved to accomodate different values. All of them are for a middle grounded (12) and the "outsides" uses a single diode.
2x240Volt uses 12 to ground 11 and 13 each with a diode to B+
2x260Volt uses 12 to ground 9 and 15 each wih a diode to B+
etc

 

[jcalvarez]

12 is the secondary center tap (CT). Then you have to select the other two wires for a full wave rectifier depending on your desired DC voltage:
11-13: 480V CT
10-14: 520V CT
9-15: 560V CT.

 

[gijser]

"Anodenmitte (12) an Masse legen"?

"connect the anode midpoint (12) to ground"

When using a rectifier tube with two anodes, these would be connected to for example 11 and 13, and 12 would then be in between the anodes and connected to ground.

 

[mdr30]

OK, now I get the picture. I was hoping to use the transformer in this PSU:

Would it work connecting 11 and 12 to the rectifier?

 

[grovergardner]

No, don't do that. Just substitute a pair of diodes for the bridge and ground 12. But be aware that the secondary is only rated for 85mA. That is probably enough for your circuit.

 

[chrisng]

Since the supply voltage is 230V and the transformer primary winding is 220V, my suggestion is: