OT hook up?

[hollisdevillo]

I have an old universal single plate OT that i found. Merit a-2902. it has two primary leads and 6 secondary lugs. On the catalog sheet i found it says the lugs are 1.5k, 2k, 4k, 5k, 7k, and 10k. but doesn't one have to be a neutral or ground or do i have to hook up between them?

http://www.bunkerofdoom.com/xfm/meri...it5111_002.jpg

thanks,

-h

[stokes]

The 1.5k,2k etc are your primaries.Dont know what those secondary ratings are .1 to 40?
What I would do is figure your turns ratio by putting a sine wave on the secondary and measure the full winding on the primary to see what you could use it for.

[Enzo]

Or perhaps it is not an output transformer but is an interstage transformer?


Why not post a scan of the catalog sheet for us?

[hollisdevillo]

the link is there (i hid it under my name), but now it is easier to see. it is a universal OT. i thought the blue and red wires were the primary? this link here shows a similar OT, but for push pull, it says to connect certain lugs for different loads.
http://www.hammondmfg.com/pdf/5c0054.pdf

i suppose there is just a lot of testing to do between each of the lugs then.

-h

[stokes]

If you look at the chart you linked,it says the multi taps are your primary.The other link you posted is for a Hammond transformer,a totally different animal.I wouldnt bother testing all the various primary taps,just test the full winding on the primary to see where you stand as to what power tube would work best/most efficiently.With your primary impedance,you dont need to match anything exactly,close enough would be good enough.You can also vary your secondary load to get you closer to a satisfactory match.I prefer to use an entire winding as opposed to using a tap somewhere in the middle of the winding,that is why I suggested to just check the outer winding tap.

[hollisdevillo]

so put a voltage across the primary lugs 1 and 6? that would be end to end i suppose? divide that by the number i see on my secondary and i'll have my turns ratio. right?
thanks guys for you help.

-h

[stokes]

I use a signal generator,put a .5 volt signal across the secondary,measure the volts you get on the full primary winding end to end and divide by .5 this gives you your turns ratio.Square the turns ratio and multiply that by your expected load,that will give you your primary impedancein ohms.