A quadrature axis is one whose magnetic effect is along the perpendicular to the field pole axis. When the peak of armature mmf coincides with the quadrature axis, the reactance offered to the armature mmf is called quadrature axis reactance.

What is the relation between XD and XQ?

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.

What are other methods to determine XD and XQ?

The method used to determine X_q and X_d, 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 direct axis Subtransient reactance?

The reactance during these first two or three cycle is least and the short circuit current is high. This reactance is called subtransient reactance and is denoted by X”. ... Since the short circuit current of the alternator lags behind the voltage by 90 degree, the reactance involved are direct axis reactance.

What is meant by synchronous reactance?

The Synchronous Reactance (X_S) is the imaginary reactance employed to account for the voltage effects in the armature circuit produced by the actual armature leakage reactance and by the change in the air gap flux caused by the armature reaction.

Concept of Direct axis and Quadrature axis & its Synchronous Reactance [xd xq] in hindi

39 related questions found

Is synchronous reactance constant?

In electrical machinery and power systems, the synchronous reactance is treated as a constant reactance in series with the generated emf and is independent of load condition.

How do you determine synchronous reactance?

1. R _a = Armature resistance.
2. X _s = Synchronous reactance ( X _L + X _a )

What is quadrature axis reactance?

A quadrature axis is one whose magnetic effect is along the perpendicular to the field pole axis. When the peak of armature mmf coincides with the quadrature axis, the reactance offered to the armature mmf is called quadrature axis reactance.

What is direct axis and quadrature axis?

The axis along the axis of the rotor is called the direct or the d axis. The axis perpendicular to the d axis is known as the quadrature or q axis. The direct axis flux path involves two small air gaps and is the path of the minimum reluctance.

What is Subtransient and transient reactance?

During first few cycles reactance of system/synchronous machine is least and short circuit current is highest. This stage is called subtransient reactance. ... After first few cycles decrement in RMS value of short circuit current is less. This state is called transient reactance and is denoted by X'.

Why field winding is kept open for slip test?

In an alternator we apply excitation to the field winding and voltage gets induced in the armature. But in the slip test, a three phase supply is applied to the armature, having voltage must less than the rated voltage while the field winding circuit is kept open.

What is leakage reactance of an alternator?

HE ARMATURE leakage may be defined as the reactance due to the difference between the total flux produced by an armature current and the flux in the airgap produced by the same armature current.

Which one of the following is reluctance power developed?

This is the power developed by cylindrical rotor machine.

Which type of rotor is best for a turbo alternator?

Smooth cylindrical type rotor is generally used for high speed alternators or turbo alternators.

Which among the following reactance have a greater value?

Synchronous reactance - Have a greater value.

Why synchronous motors are not self starting?

Above a certain size, synchronous motors are not self-starting motors. This property is due to the inertia of the rotor; it cannot instantly follow the rotation of the magnetic field of the stator. ... Once the rotor nears the synchronous speed, the field winding is excited, and the motor pulls into synchronization.

What is Axis reactance?

A direct axis quantity is one whose magnetic effect is along the field pole axis. Based on this fact, a direct axis synchronous reactance is defined as the reactance offered to the armature flux when the peak of armature mmf is directed along the direct axis. ...

Is the angle between stator direct axis and quadrature axis?

What is the angle between stator direct axis and quadrature axis? Explanation: In reluctance motor, direct axis is horizontal axis and quadrature axis is at 90° to the direct axis. Explanation: Space angle is measured between stator direct axis and long rotor axis.

What is Potier triangle?

Potier Triangle is a right angled triangle whose perpendicular and base represents the voltage drop in armature leakage reactance (I_ax_al) and armature mmf F_a respectively. This triangle is used to draw the zero power factor characteristics (zpfc) from the open circuit characteristics (OCC) of synchronous generator.

What is V curve in synchronous motor?

V-curve of a synchronous machine shows its performance in terms of variation of armature current with field current when the load and input voltage to the machine is constant.

What is the use of damper winding?

Damper windings helps the synchronous motor to start on its own (self starting machine) by providing starting torque. By providing damper windings in the rotor of synchronous motor “Hunting of machine”can be suppressed.

What is hunting in electrical machine?

The word hunting is used because after the sudden application of load the rotor has to search or 'hunt' for its new equilibrium position. That phenomenon is referred to as hunting in a synchronous motor. ... In steady state, rotor runs at synchronous speed thereby maintaining a constant value of torque angle (δ).

What is electronic reactance?

reactance, in electricity, measure of the opposition that a circuit or a part of a circuit presents to electric current insofar as the current is varying or alternating. Steady electric currents flowing along conductors in one direction undergo opposition called electrical resistance, but no reactance.

What is synchronous reactance and synchronous impedance?

Both the armature reaction reactance and the leakage reactance are present at the same time. The two raeactances are combined together and the sum is called the Synchronous reactance (Xs). X_s = X_al + X_ar. The combined result of the Synchronous reactance and armature resistance is called Synchronous Impedance (Zs).

What is alternator reactance?

We have determined that reactance values are a measure of an Alternator's 'magnetic. stiffness' and are used as a mathematical modelling tool to help describe the performance of. an alternator under the different stages of behaviour during fault conditions. The reactance is.