whit3rd wrote:



NO, that's exactly backwards: a 'free' transformer with negligible
secondary current DOES near-saturate.
The primary current and secondary current are in
the opposite direction, so load (secondary) current CANCELS
the magnetization caused by the drive (primary) current.

A lot of secondary current (high load current) removes the
risk of saturation.


** While adding load current does not directly alter the magnetising current in the primary, it does reduce the effective AC supply voltage seen by the primary.

This is due simply to the resistance of the primary winding - current flow produces a voltage drop which must be subtracted from the external supply voltage to accurately model what is going on.

Eg, say the primary current due to load is 1 amp and the winding has 5 ohms resistance - then the effective voltage is 5 volts LESS than the AC supply.


..... Phil

..... Phil