GEC BRT400 - suspected duff mains transformer - Page 2 - UK Vintage Radio Repair and Restoration Discussion Forum

Tim · 14th Oct 2009, 9:01 pm

Quote:

The other thing to look at is the lam securing bolts. These usually have insulating washers under their heads. Without them it is possible to get the effect of a shorted turn

Could one use nylon bolts if this proves to be troublesome?

Herald1360 · 14th Oct 2009, 10:48 pm

I doubt they would stand the normal operating temperature without softening and relaxing any grip they may have had to start with. Stainless steel has quite a high resistivity, but I guess would still need some insulation.

cmjones01 · 15th Oct 2009, 9:56 am

Rob, the idea of turns shorting to the screen or core is a possibility, so I'll try that test when I get the transformer out. It'll be more out of curiosity than anything else - whatever happens, the transformer will be little more than a paperweight.

The lamination clamp bolts seem undisturbed. They have pillars screwed to the ends which support the transformer away from the chassis, so I can't check those until I've removed the whole thing.

14th Oct 2009, 10:48 pm	#22
Herald1360 Dekatron Join Date: Feb 2007 Location: Leominster, Herefordshire, UK. Posts: 16,535	Re: GEC BRT400 - suspected duff mains transformer I doubt they would stand the normal operating temperature without softening and relaxing any grip they may have had to start with. Stainless steel has quite a high resistivity, but I guess would still need some insulation.

15th Oct 2009, 9:56 am	#23
cmjones01 Nonode Join Date: Oct 2008 Location: Warsaw, Poland and Cambridge, UK Posts: 2,677	Re: GEC BRT400 - suspected duff mains transformer Rob, the idea of turns shorting to the screen or core is a possibility, so I'll try that test when I get the transformer out. It'll be more out of curiosity than anything else - whatever happens, the transformer will be little more than a paperweight. The lamination clamp bolts seem undisturbed. They have pillars screwed to the ends which support the transformer away from the chassis, so I can't check those until I've removed the whole thing.