What is XD and XQ in synchronous machine?
Xd- Direct-axis Synchronous Reactance the ratio of fundamental A.C. armature Voltage to A.C. armature current produced by the direct-axis flux. Xq- Quadrature-axis Synchronous Reactance the ratio of fundamental A.C. armature Voltage to A.C. armature current produced by the quadrature-axis flux.
Which formula is correct while measuring reactance XD and XQ of an alternator by slip test?
Explanation: Xd=V(max)/I(min) = 30/5 = 6 ohms; Xq=V(min)/I(max) = 25/10 = 2.5 ohms.
What is salient pole synchronous machine?
Salient Pole Synchronous Alternator: Salient pole Generators will have large diameter and short axial length. Pole shoes cover 2/3 of the pitch. Salient Poles are laminated in order to reduce eddy currents. They are used in hydraulic turbines or diesel engines.
What does slip test mean?
Slip test is performed on salient pole synchronous machine to determine the direct axis reactance and quadrature axis reactance.
What is a salient pole?
: a magnet pole that projects toward the armature of an electric machine — compare consequent pole.
What is d axis and q axis?
The d axis, also known as the direct axis, is the axis by which flux is produced by the field winding. The q axis, or the quadrature axis is the axis on which torque is produced. By convention, the quadrature axis always will lead the direct axis electrically by 90 deg.
What are other methods to determine XD and XQ?
The method used to determine Xq and Xd, the direct and quadrature axis reactance is called slip test. Current induced in the damper winding of alternator will produce an appreciable error. Induced voltage in the open circuit field may reach dangerous values.
What is slip formula?
Slip speed is the speed difference between the Synchronous speed and Rotor speed. Slip speed = Synchronous speed – Rotor speed = Ns -N. Slip, s = (Ns – N) / Ns.
What is difference between salient pole and non salient pole?
The third difference between salient pole and cylindrical pole is that the cylindrical pole (non-salient) design is much more durable and has a much lower winding loss than a salient pole unit. Next, its diameter is smaller but the axial length is longer. Also, both winding and noise are less than salient polar rotors.
What does salient pole mean?
What is a salient pole rotor?
What are Salient Pole rotors? Salient pole rotors are large in diameter and shorter in length. They are typically used in lower speed electrical machines (100 RPM to 1500 RPM). Salient pole rotors normally require damper windings to avoid oscillations of rotors during operation.
What is salient pole and non salient pole?
Is there way to make XD and Xq in salient pole machines equal?
Xd and Xq are present in salient pole alternators where (Xd> Xq). So in order to make Xd and Xq equal, all you need to do is to change the salient pole machine in to uniform air gap machine such as cylindrical rotor alternator .
How is the flux of XD and Xq determined?
When the stator m.m.f. is aligned with the q-axis of field poles then flux Φ q per pole is set up and the effective reactance offered by the alternator is X q. As the air gap is nonuniform, the reatance offered also varies and hence current drawn the armature also varies cyclically at twice the slip frequency.
How is the salient pole synchronous machine two Rection theory?
Salient Pole Synchronous Machine Two Rection Theory. In the cylindrical rotor synchronous machine, the air gap is uniform. The pole structure of the rotor of a salient pole machine makes the air gap highly non-uniform. Consider a 2 pole, salient pole rotor rotating in the anticlockwise direction within a 2 pole stator as shown in the figure below.
How is the air gap uniform in a salient pole synchronous machine?
In the cylindrical rotor synchronous machine, the air gap is uniform. The pole structure of the rotor of a salient pole machine makes the air gap highly non-uniform. Consider a 2 pole, salient pole rotor rotating in the anticlockwise direction within a 2 pole stator as shown in the figure below:
