Synchronizing Power and Synchronizing Torque

Which of the following makes synchronizing power to come to play in the machine

Which of the following is/are used in synchronous machines to maintain mechanical stability?

The coupling angle or load angle of a synchronous motor is defined as the space angle between

An over excited synchronous machine is more stable than under excited

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

Large stiffness coefficient represents

Synchronizing power is
(i) Stiffness coefficient of electromagnetic coupling between stator and rotor
(ii) Stability measure of synchronous machine
(iii) Power consumption factor

For a 4-pole 3 phase, 400V alternator has synchronizing power of 300 units. Then the synchronizing power per mechanical degree is

Electromagnetic torque is present in rotating machines when

Synchronizing power is

Which motor can conveniently operate at lagging as well as leading power factor?

In a synchronous motor the back emf peak set up in the stator depends on

The operation of a synchronous motor operating on constant excitation across infinite bus will not be stable if power angle δ

Variation in the dc excitation of a synchronous motor causes variation in

As load angle is increased, degree of stability _________