I was completing a question for homework and I don't really understand the answer. The question says that when a core goes from being laminated to unlaminated the voltage across the secondary coil goes down and it asks to explain why. The only thing I could think of was heat loss due to eddy currents. However, although this was mentioned in the answer it also said the following:
eddy current create magnetic flux This flux opposes flux from primary coil Max flux from primary coil is reduced Max rate of change of flux reduced so emf across secondary is reduced.
Thinking about this I don't understand how the back emf works. Take this as an example. Consider a power station is putting out a certain amount of power - call it 100 (arbitrary units) then the power at the primary is 100. Let us ignore the heat loss from eddy currents which will mean that the power at the secondary is also 100. However, even if you could eliminate heat loss from eddy current (e.g. superconductor) surely they would still create a back emf which would reduce the flux from the primary and hence reduce the emf at the secondary which would mean the power is NOT 100. So where would the missing energy go?