
AC Generator 87
Therefore, for the same load power, the salient-pole machine would naturally run at
lower δ. Further, having higher P
max
, it can take a slightly greater step load change
than the round rotor machine of comparable design before losing the transient stabil-
ity limit discussed in the next section.
4.4 TRANSIENT STABILITY LIMIT
The maximum power limit P
max
at δ = 90° in Figure4.8(a) for the cylindrical rotor
is called the steady-state stability limit. Any swing in δ beyond 90° may cause the
rotor to lose synchronism and its power generation capability. Therefore, it is desir-
able to keep δ below 90° under all conditions, includi ...