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SEE 3433 MESIN ELEKTRIK. SYNCHRONOUS MACHINES Power and Torque Characteristics. jX s. R a. + V t . I a. + E f . This gives :. Active power. Reactive power. Power and Torque Characteristics. Let V t = V t 0 o. E f = E f o. Complex power is given by:.
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SEE 3433 MESIN ELEKTRIK SYNCHRONOUS MACHINESPower and Torque Characteristics
jXs Ra + Vt Ia + Ef This gives : Active power Reactive power Power and Torque Characteristics Let Vt = Vt0o Ef = Efo Complex power is given by: S = VtIa* = P + jQ
P = Active power = Q = Reactive power = Power and Torque Characteristics S = VtIa* = P + jQ If |Z| = Xs hence = 90o
P, T Pmax Tmax 90o Power and Torque Characteristics
P, T Pmax Tmax 90o Power and Torque Characteristics The machine will loose synchronism when the power angle, greater than 90o e.g. generator operation. As prime mover power increased, generator need to produce torque to ‘pull’ machine to synchronism – limit when =90o The Tmax or Pmax can be increased by increasing the field excitation