Thermal protection of mains transformers - Page 2 - UK Vintage Radio Repair and Restoration Discussion Forum

broadgage · 17th Dec 2018, 5:15 pm

A lot of cheap appliances may be designed primarily for 220 volt mains, Running a 220 volt transformer on our mains which is still 240 volts most of the time in most places, will increase the magnetising current and therefore the heat.

Refugee · 17th Dec 2018, 5:16 pm

The type approval houses only measure the outside of the case.
A transformer can be as hot as the manufacturer can get away with inside the case.

17th Dec 2018, 5:15 pm	#21
broadgage Nonode Join Date: Jan 2010 Location: North Somerset, UK. Posts: 2,129	Re: Thermal protection of mains transformers A lot of cheap appliances may be designed primarily for 220 volt mains, Running a 220 volt transformer on our mains which is still 240 volts most of the time in most places, will increase the magnetising current and therefore the heat.

17th Dec 2018, 5:16 pm	#22
Refugee Dekatron Join Date: Apr 2012 Location: Worksop, Nottinghamshire, UK. Posts: 5,553	Re: Thermal protection of mains transformers The type approval houses only measure the outside of the case. A transformer can be as hot as the manufacturer can get away with inside the case.