I was reading this answer and I would like to understand why if the secondary is short circuited the primary winding will also reflect the short circuit despite the fact that they are isolated. Would the electromagnetic flux through the core be increased with a short circuit on the secondary? If the secondary is shorted I guess it would be as if no turns were present. How would that draw more current from the supply at which the primary is connected?
A transformer uses feedback between secondary to primary, via the core flux, and requires some LOW series impedance between the primary voltage source and the voltage across the internal primary N*dphi/dT. Call this voltage the feedback-voltage.