Understanding Power Transformer Wiring

[ron_swanson]

I have a transformer that was recommended on a BOM for a build I'm working on at the moment where I'm a little unsure of how to wire up.  Normally the datasheets I have used in the past for simular builds included a few simple connection examples / diagrams that assisted with confirming correct configuration and have always included a clearly defined center tap (This is for a tube build).  In this case, there's only a schematic.  Hoping someone can help verify what I'm thinking or provide some insight for further learning or configuration in case I'm way off base.  See attachment.

I'm in the US running 120V. 

Would I wire the primary side with both red wires connected together and both black wires connected together? The shield goes to ground? 

Secondary 275V HT would have have both white wires tied together and both yellow tied together?  If so, would that then make the yellow wire the CT or will I need ot create a virtual CT using this transformer configuration?

Also on the secondary, the two blue 6.3v wires are tied together and the two green wire tied together?

Or, are all of the above secondaries two separate power feeds - meaning two 275V and two 6.3V feeds?

Also open to online documentation if there's a website that goes into specific detail about something like this.

Thanks in advance!

 

[Matador]

The wiring depends on what voltages/currents you need.

For 120V US, you wire the primaries in parallel (red to red, black to black).

For secondaries:  it depends on what secondary voltages you need.  If you need a 275V supply, you can wire the secondaries in parallel, however there won't be a center tap (you'll have to create one).  If you need 550V, you wire the secondaries in series, and you can use the center tap that's formed.  The same goes for the heater secondaries (wire them in parallel if you need 6.3V, series if you need 12.6V, and you get a center tap if needed).

 

[ruffrecords]

If you look at the current rating for each winding you quickly realise that the HT secondary is intended you use the two winding in series, with each winding conducting in only half the mains cycle. To Explain.

The 2 x 6.3V winding each can supply 3A which is a total of 2 x 6.3 x 3 = 37.8VA.

The transformer is rated at 100Va so there is an expectation that not more than 60VA will be taken from the HT windings. However, each 275V winding is rated at 0.18A which is 275 x 0.18 = 49.6VA. Clearly you cannot take this current out of both HT windings. SO clearly it is intended to be used in a circuit like the top one shown here:

https://www.sowter.co.uk/rectifier-transformer-calculation.php

Cheers

Ian