Guru
Joined: 09/08/2007
Location: AustraliaPosts: 4406
| Posted: 06:21am 12 Apr 2021 |
Yes indeed Phil.
You just need to energise the core with a few turns to reach the desired flux density you wish to test at, and the Va required will be the same regardless of the number of turns on the final windings.
Only difficulty is that without first stripping the transformer, there is no real way to measure the core cross sectional area, and that area is the basis of all the design equations regarding the core.
Strictly speaking, core "loss" is only the resistive in phase component of the current which generates heat directly into the core material through hysteresis and eddy current effects.
There is also an inductive component (Xl) which generates an out of phase current. Higher inductance reduces that part of the idling current. Better steel has a higher permiability than junk steel, and more inductance per turn as a result.
Its more common to lump the whole lot together as idling Va's, its much easier to measure anyway. So the lower the idling power the more power efficient an inverter will be at low loading.