The subtransient reactance of a synchronous generator is

The subtransient reactance of a synchronous generator is much less than its synchronous reactance in the initial phase of short circuit from no load as

1. magnetizing ampere-turns appear because of induced field and damper winding current as the air-gap flux cannot change instantaneously from its no load value.
2. demagnetizing ampere-turns appear because of induced filed and damper winding currents as the air -gap flux cannot change instantaneously from its no-load value.
3. magnetizing ampere-turns, appear because of induced field and damper winding currents as the air-gap flux must reduce instantaneously from its no-load value.
4. demagnetizing ampere-turns appear because of induced field and damper winding currents as the air-gap flux must reduce instantaneously from its no-load value.