R-core mains transformer problem

[N_Cook]

300W transformer that over 4 years of use, the secondary voltages are 10
percent lower than originally, at least. Measuring without full rated
loading, so worse than that under load presumably.
If the transformer was severely jarred, via its mounting bolts, could that
open up the core closure and consequential drop in efficiency or some other
R-core type generic reason for drop? will it get worse over more time?

 

[Joerg]

Either a shorted turn or a loss of permeability sufficient to drop the
output voltage 10% would make the transformer get very hot.

Aha! Now we know what caused global warming.

 

[Phil Allison]

"Nutcase _Kook"

300W transformer that over 4 years of use, the secondary voltages are 10
percent lower than originally, at least.

** No they are NOT and you have no evidence any such thing has happened.

Voltages marked on a PCB are not proof of your wacky assertion.


Quote from same lunatic 2 days ago:

" The one in front of me gives off various voltages and the associated DCs
are
marked on the overlay (no schematic available).
All the DC voltages , amplifier but just quiescent no load, all the actual
DC levels are about 10 percent less than the overlay marked DC. "

Go away.



..... Phil

 

[Fred Abse]

300W transformer that over 4 years of use, the secondary voltages are 10
percent lower than originally, at least. Measuring without full rated
loading, so worse than that under load presumably.
If the transformer was severely jarred, via its mounting bolts, could that
open up the core closure and consequential drop in efficiency or some other
R-core type generic reason for drop? will it get worse over more time?

Looks like you're in the UK.

UK mains voltages fluctuate. 10% isn't unusual, in fact, I believe it's
permitted.

AIUI, the UK is having an unusually cold period. Voltages are likely down.

Could explain things. Have you measured the supply voltage? If not, go do
it, measure the secondary voltage, calculate the turns ratio then come
back and tell us whether you still think the transformer is NG.