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saba: Power transformer

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Forum » Radios and other type of sets (Physics) etc. » MODELS DISPLAYED » saba: Power transformer
           
Roy Sheppard
 
 
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15.Jan.20 15:32
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The mains transformer on my Wildbad 11 is faulty. It stopped working and I found the fuse had blown. I replaced the fuse and switched the radio on and there was a puff of smoke from the mains transformer. Does anyone know where I can get a new transformer that works on a 230-240V supply? I thought that this problem might happen someday as the highest tap on the transformer was 220V so it was running over the design value.

I checked the insulation to ground at 600V and there was no problem. The primary winding resistance measures about 30Ω.

Best regards

Roy Sheppard

James MacWilliams
 
 
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24.Jan.20 14:37

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Roy,

Are you absolutely certain the fault does not lie on the secondary side of the transformer?  Have you isolated all the secondary windings such that there is no load at all?  The 30 ohms for the primary sounds reasonable, but there could be shorted windings in the primary.  I recently had a similar problem in a Saba Meersburg and the problem was indeed in the transformer.  I was able to find a suitable replacement on eBay (the German site).

The other option, if indeed the transformer is bad, is to have it rewound.  There is a gentleman in England who rewinds transformers.  If you get it rewound, you can have it rewound for 230-240V.

Finally, once you have a replacement, assuming it is a 220V version, insert a small dropping resistor in series with the primary to drop the incoming voltage to 220.

Roy Sheppard
 
 
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01.Feb.20 12:49
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James

Thanks for the info. I am reasonably certain that the transformer primary is the problem especially when blue smoke comes out just before the fuse blows. Probably shorted turns. There is no sign of any short-circuits or abnormally low resistance on the DC HT side. I have been unable to find an off-the-shelf transformer with the correct electrical and mechanical specifications so I have now located a UK firm that can custom-make a transformer to your specification. They have a 40W base design that has the same footprint as the old item that I am getting wound with the required SABA outputs. This will have a European primary covering 200-250V. The downside is the cost, about £220, and 5-6 week delivery!

For future reference, the firm is  EA Sowter Ltd, The Boatyard Cullingham Road, IPSWICH Suffolk IP1 2EG, UK. Sorry, I could not get a click-to-link to work on this editor. I am reasonably savvy with PC stuff and having used the link window correctly, it refuses to submit.

Best regards

Roy

  
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