Consider the below remarks for an alternator.(i) An over excited machine is more stiff(ii) Machine with longer air-gap is less stable than one with smaller air-gap

Synchronous Machine Stability topics include: Synchronizing power and synchronizing torque, hunting and damper windings and synchronous machine stability. A synchronous machine's steady-state stability limit is 2.2 pu when connected to an infinite bus. In this case, the infinite bus voltage is 1pu, and the synchronous machine voltage is 1.1 pu.  Synchronous machine stability is related to how the machine responds to a gradually increasing load. It's concerned with finding the upper limit of machine loading without losing synchronism, as long as the loading is increased gradually.  A slight... Show more

Synchronous Machine Stability topics include: Synchronizing power and synchronizing torque, hunting and damper windings and synchronous machine stability.

A synchronous machine's steady-state stability limit is 2.2 pu when connected to an infinite bus. In this case, the infinite bus voltage is 1pu, and the synchronous machine voltage is 1.1 pu. 

Synchronous machine stability is related to how the machine responds to a gradually increasing load. It's concerned with finding the upper limit of machine loading without losing synchronism, as long as the loading is increased gradually. 
A slight increase in load can lead to instability and loss of synchronism.

Related: Electrical Machines Practice Test: Synchronous Machines

Show less