Transformer help needed

Well I've traced what I think is a fault on my genny to an open circuit 3 phase transformer. It's delta wired with quite thin primary and thicker secondary. All 3 primary windings show open circuit with my multimeter. I've spend most of the afternoon whistling Old MacDonald's Farm to myself as I stripped out the laminations removing E's and I's interspersed with frequent oh's. I now have a pile of said E's and I's and some wire on order to try rewinding the coils. Fortunately the primary=92s are on the outside. Inevitably, 3 or 4 E=92s broke during dismantling. I=92m working on the basis that 3 out of 120 aren=92t significant and I will probably have trouble getting them all back in anyway. The transformer=92s on the excitation circuit BTW. Is there anything I should be aware of or should I give up now? Would a rewind company do a much better job on a purpose made machine? If so, is it worth just paying them to do it for me?

Thanks in advance

John

Reply to
John
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"John" wrote

Well I've traced what I think is a fault on my genny to an open circuit 3 phase transformer. It's delta wired with quite thin primary and thicker secondary. All 3 primary windings show open circuit with my multimeter. I've spend most of the afternoon whistling Old MacDonald's Farm to myself as I stripped out the laminations removing E's and I's interspersed with frequent oh's. I now have a pile of said E's and I's and some wire on order to try rewinding the coils. Fortunately the primary?s are on the outside. Inevitably, 3 or 4 E?s broke during dismantling. I?m working on the basis that 3 out of 120 aren?t significant and I will probably have trouble getting them all back in anyway. The transformer?s on the excitation circuit BTW. Is there anything I should be aware of or should I give up now? Would a rewind company do a much better job on a purpose made machine? If so, is it worth just paying them to do it for me?

I'd recommend taking it to a rewind shop. You'll be extremely lucky if you can wind as neatly as if it were done on a coil winder, which means that you won't be able to fit the correct number of turns on the bobbin.

Above all, don't remove the failed windings - the rewind shop will need to know the number of turns to perform the rewind.

If you have a specification for the transformer, you could think about getting a new one made. They aren't that expensive.

Reply to
John

Give me some accurate dimensions and I'll see if any of our standard lam's wll fit. Also need the thickness. 0.050" are standard 800/50 or 400/50 grade, there are also higher-spec/thinner lams and GO (Grain Orientated) types.

Peter

-- Peter A Forbes Prepair Ltd, Rushden, UK snipped-for-privacy@prepair.co.uk

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Reply to
Peter A Forbes

Thanks John and Peter for your help. Unfortunately I don't have any details about the alternator, let alone the excitation transformers I spoke a rewind company and their price made me sit down. I'm now looking at other ways around it. Thanks again.

John

Reply to
John

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