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1100 man · 24th Oct 2017, 8:51 pm

Hi John,
Do you have any theories as to exactly how the transformer is failing? Obviously heat is the key element here: everything is fine when the transformer is cold but what is happening within the LOPT as it gets hot? I guess the resistance of the windings will increase, but I wouldn't think that would affect things much. Presumably shorted turns would have a much more significant effect than a small loss of width? You mention core saturation- does that get worse the hotter it gets?
Some LOPT's do seem to get worryingly hot after 1/2hr or so. Some of the Ekco chassis from the late '50's (of which I have several)have a 2" hole under the LOPT which will take a small cooling fan. This dramatically reduces the temperature of the transformer and hopefully increases their lifespan!!
All the best
Nick

24th Oct 2017, 8:51 pm	#20
1100 man Octode Join Date: Apr 2016 Location: Ventnor, Isle of Wight, & Great Dunmow, Essex, UK. Posts: 1,377	Re: KB VC1 width problem Hi John, Do you have any theories as to exactly how the transformer is failing? Obviously heat is the key element here: everything is fine when the transformer is cold but what is happening within the LOPT as it gets hot? I guess the resistance of the windings will increase, but I wouldn't think that would affect things much. Presumably shorted turns would have a much more significant effect than a small loss of width? You mention core saturation- does that get worse the hotter it gets? Some LOPT's do seem to get worryingly hot after 1/2hr or so. Some of the Ekco chassis from the late '50's (of which I have several)have a 2" hole under the LOPT which will take a small cooling fan. This dramatically reduces the temperature of the transformer and hopefully increases their lifespan!! All the best Nick