Hi everyone
Though I'd get going straight away with my first post ,
any ideas what this is?
It has a sticker with 'Carnhill Transformers' H-M266A-01 on the top and what appears to be 3 primary and 7 secondary on the pins....there are also two wires either side
steer me in the right direction, i'm a newbie !
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For starters, see if you can set your DMM to Ohms, figure out where the ends of each winding are terminated, and tell us how many Ohms on each winding.
On the top picture, at the very left, you can see fairly fat wire coming up from the bobbin to the far left pin and the one next to it. Call these pins 1 and 2. It is likely that's a filament winding. Pins 3 and 4 have slightly thinner wire. I am going to suggest those are also a filament winding. Pins 5, 6 and 7 might have wire that is thin enough to be the high voltage secondary. See if Ohms are approximately equal from 5-6 and 6-7. Then it looks like there are 3 pins on the right will yellow sleeving. Can't see the wire size, so it's harder to guess. With a CT, it might be another filament winding or it might be the high voltage secondary.
On the other side, I'll assume you received this with the reds twisted and the greys twisted. I think that means this is a gual voltage primary. For 120V, you can parallel the windings and that is why they are twisted. When you parallel a pair of primaries, you get double the mA capacity. If you need to use it for 240, you wire in series and because you input 2x on the pirmary, you only get half the mA capacity, but the VA is the same. if you separate them at the ends, I think you'll find two windings that are not connected. The Ohm reading on the primary side is a very good hint at the overall VA capacity. Tell us, what are the Ohms on each one separately? An then in parallel, they should be half that.
Once you determine what pairs up, find a low AC voltage source. Most wall warts are DC, but sometimes you can find an AC one. The filament winding from a known power transformer is a good source for the primary. A 10V source is ideal because it makes the math easy, but there is otherwise no magic to it. Putting voltage on the primary will allow you to find out what the secondary voltages are. Remember, this is unloaded AC output, which will be higher than actual in circuit use.
I have just metered the transformer, every winding is exactly 0.8 ohms
It looks like the wire on windings 5 , 6, and 7 is very thin
the orange wires and grey wires both meter 0.8 on their own and in parallel together,
in series they measure 0.9 ohms
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What brand of meter are you using? Some simply can't resolve DCR when it is that low. At least you should know how it pairs up now. If you don't have a low voltage a/c source, put a cord on the primary and plug it in. Then you'll know the unloaded output voltages. I would fuse the hot leg even for the test. You should be fine with a 1A slo blo. Or else, use a power strip/surge protector with a breaker on it -- standard fare for plugging in most computer equipment..
!