PHASER DIAGRAM OF SYNCHRONOUS RELUCTANCE MOTOR
The synchronous reluctance machine is considered as a balanced three phase circuit, it is sufficient to draw the phasor diagram for only one phase. The basic voltage equation neglecting the effect of resistance is
V = E – j IsdXsd – j Isq…………(1.1)
V is the Supply Voltage
Is is the stator current
E is the excitation emf
Ȣ is the load angle
ɸ is the phase angle
Xsd and Xsq are the synchronous reactance of direct and quadrature axis
Isd and Isq are the direct and quadrature axis current
I = Isd + Isq…………….(1.2)
Isd is in phase quadrtur with E and Isq is in phase with E.
V = E – j IsdXsd – j IsqXsq
Equation (9) is the torque equation of synchronous reluctance motor.
Plotting the equation (9) as shown in fig indicates that the stability limit is reached at Ȣ =± ᴨ /4
And by increasing g load angle torque also increases.
In synchronous reluctance motor, the excitation emf(E) is zero.