What is the relation between torque and rotor power factor?
Equation of Maximum Torque The maximum torque is directly proportional to square of rotor induced emf at the standstill. The maximum torque is inversely proportional to rotor reactance. The maximum torque is independent of rotor resistance. The slip at which maximum torque occur depends upon rotor resistance, R2.
What is the load angle mean?
As discussed earlier in this post, load angle is the angle between the field flux and the resultant air gap flux. This means, as the mechanical power input to the synchronous generator is increased through prime mover, the field poles will be dragged ahead of the stator pole or flux.
How is rotor current calculated?
- Ns is the synchronous speed.
- and Nr is the rotor speed.
- Rotor current frequency (fr) = (s)(f)
- Rotor current frequency (fr) = 0.05 x 50.
- fr = 2.5 Hz.
What is rotor power factor?
The rotor power factor is found using θ = tan-1(X2/R2/s) = tan-1(1.066/7.7) = 7.88° and PF = cos(7.88°) = 0.991 and is stated to be lagging.
What is the ratio of rotor copper loss and rotor input?
In an induction motor, what is the ratio of rotor input to rotor copper loss? Rotor copper loss = S × Rotor input power ∴ Rotor input / Rotor copper loss = 1/S.
What is the power factor angle?
The power factor of an AC circuit is defined as the ratio of the real power (W) consumed by a circuit to the apparent power (VA) consumed by the same circuit. When the power factor equals zero (0), the phase angle between the current and the voltage will be 90o as: cos-1(0) = 90o.
What is power factor cosine angle?
The Cosine of angle between Current and Voltage is called Power Factor. P = VI Cosθ OR. Cosθ = P / V I OR. Cosθ = kW / kVA OR. Cosθ = True Power/ Apparent Power.
What is rotor angle?
Rotor angle is the position of the rotor relative to the terminal voltage. The relative angle between these two sinusoidally varying quantities has a direct relation to the power output of the machine. In all machines there are mutual inductances that exist between the rotor and the stator.
Why rotor angle is called load angle?
Load angle is nothing but an angle different between stator axis and rotor pole axis of the synchronous motor. The motor has both mechanical and electrical losses, hence load angle is always present in the synchronous motor.
What is rotor current?
Locked rotor current is basically the current drawn by the motor at its rated voltage when its rotor is kept stationary or in other words rotor is not spinning or rotating. So when we start a motor, its rotor is already at rest. This means, starting current and locked rotor current should be same.
What is rotor voltage?
In the case of an asynchronous machine where the winding of the rotor coupled in star or delta configuration, the rotor voltage is linked to the slip which is the difference between the speed of the flow and the speed of the rotor.
How is the power angle of a generator defined?
Power angle can also be defined in terms of armature or stator mmf and resultant air gap mmf. In a synchronous generator, the stator mmf lags behind the resultant air gap mmf. This angle of lag is called load or power angle. Significance of Load Angle
Why is increase in load angle known as power angle?
From the above expression, it is clear that increase in angle δ increases the power output provided field excitation and generator terminal voltage is kept constant. This is the reason, load angle is also known as power angle. Now you might think, can we keep on increasing the load angle to increase the generator output?
Why is the rotor power factor of the induction motor?
As to why, the rotor current is induced BY the stator current. So when acting as a motor, it is ALWAYS going to be taking place AFTER the stator induces it. Power Factor is just the measurement of that lag. Thanks for contributing an answer to Electrical Engineering Stack Exchange!
What is the load angle of a synchronous generator?
As discussed earlier in this post, load angle is the angle between the field flux and the resultant air gap flux. This means, as the mechanical power input to the synchronous generator is increased through prime mover, the field poles will be dragged ahead of the stator pole or flux. This in turn will increase the load angle.