- #1
nand arora
- 16
- 0
What will happen if the rotor is made to rotate at double the synchronous speed i.e slip becomes less than -1. I have never seen any diagram showing torque slip curve with slip less than -1.
subtech said:At what speed does the rotor operate under normal conditions?
subtech said:At what speed does the rotor operate under normal conditions?
nand arora said:Why the portion of curve with speed above twice the synchronous speed not been shown in generating action?
Will there be something similar to braking that will take place here as this part of the curve is mirror image of that part.
This can be obtained by plugging i.e. say initially stator magnetic field was rotating in clockwise direction and for breaking we reversed the connections. Thus stator magnetic field starts rotating in anti-clockwise direction while the rotor still rotates in clockwise direction. Thus we get slip greater than one.
nand arora said:But I want to ask about generating mode. Will there be some action similar to braking action in slip between -1 to -2 as this part of the curve is mirror image of the part with slip between 1 to 2 (braking action). Probably nothing should happen as such.
Why not ?nand arora said:I also want to know that can we take the slip to any negative value say -3 or even -4 (theoretically) as we can make the rotor to rotate at 4 to 5 times the synchronous speed in direction of the rotating magnetic field.
jim hardy said:It might be helpful to imagine yourself very small and riding on the surface of the rotor with a magnetometer.
Torque reverses when slip changes sign. That's the RPM where your magnetometer would show flux reversing its direction of apparent motion, ie North ceases to overtake you and you commence to overtake North, passing it once per slip cycle.
The only place where slip changes sign is at zero slip, ie synchronous speed.
So torque ought to asymptotically approach zero. Well, discounting friction and windage. Make that electromagnetic torque .
A poly-phase induction generator is an electrical machine that converts mechanical energy into electrical energy. It uses electromagnetic induction to generate electricity by rotating a set of windings within a magnetic field.
A poly-phase induction generator works by rotating a set of windings, known as the rotor, within a magnetic field created by the stator. This movement induces an electrical current in the rotor windings, which is then collected by stationary contacts called slip rings. The electrical current is then transferred to an external circuit for use.
Poly-phase induction generators have several advantages, including high efficiency, low maintenance, and simple construction. They are also self-starting and do not require a separate DC power source. Additionally, they can operate at variable speeds and can handle large variations in load without affecting their performance.
Poly-phase induction generators are commonly used in renewable energy systems, such as wind turbines and hydroelectric power plants. They are also used in industrial applications, such as powering machinery and equipment. In addition, they can be used in emergency backup systems and as a source of electricity in remote locations.
While poly-phase induction generators have many advantages, they also have some limitations. They are not suitable for applications that require precise control of output voltage or frequency. They also have a limited speed range, and their performance can be affected by variations in load or voltage. Additionally, they may produce harmonic currents, which can cause power quality issues.