![C400 Snap-action switches](http://s1.studyres.com/store/data/007792242_1-2d33c37b82bb0db2271f1342deceb860-300x300.png)
10. electro magnetism
... i. Whenever there is a change in the magnetic flux linked with a coil, an emf is induced. The induced emf lasts as long as there is a change in the magnetic flux linked with the coil. ii. The magnitude of the emf induced is directly proportional to the rate of change of the magnetic flux linked with ...
... i. Whenever there is a change in the magnetic flux linked with a coil, an emf is induced. The induced emf lasts as long as there is a change in the magnetic flux linked with the coil. ii. The magnitude of the emf induced is directly proportional to the rate of change of the magnetic flux linked with ...
Induction Motor and Faults
... Two sets of bearings are placed at both the ends of the rotor of an induction motor to support the rotating shaft. They held the rotor in place and help it to rotate freely by decreasing the frictions. Each bearing consists of an inner and an outer ring called races and a set of rolling elements cal ...
... Two sets of bearings are placed at both the ends of the rotor of an induction motor to support the rotating shaft. They held the rotor in place and help it to rotate freely by decreasing the frictions. Each bearing consists of an inner and an outer ring called races and a set of rolling elements cal ...
Sensored Field Oriented Control of 3
... requires brushes to obtain its current supply and generate rotor flux. The contacts are made of rings and have many commutator segments. The drawbacks of this type of structure are maintenance needs and lower reliability. Replacing the common rotor field windings and pole structure with permanent ma ...
... requires brushes to obtain its current supply and generate rotor flux. The contacts are made of rings and have many commutator segments. The drawbacks of this type of structure are maintenance needs and lower reliability. Replacing the common rotor field windings and pole structure with permanent ma ...
(ii) Three-phase transformer
... The basic principle behind working of a transformer is the phenomenon of mutual induction between two windings linked by common magnetic flux. Basically a transformer consists of two inductive coils; primary winding and secondary winding. The coils are electrically separated but magnetically linked ...
... The basic principle behind working of a transformer is the phenomenon of mutual induction between two windings linked by common magnetic flux. Basically a transformer consists of two inductive coils; primary winding and secondary winding. The coils are electrically separated but magnetically linked ...
An Improved Weighted Total Harmonic Distortion Index for Induction
... and resistance is again valid for the stator circuit of any random wound ac machine. However, the shorted bars of the rotor of an induction motor produce special problems due to deep bar effect which causes the rotor current to rise to the air gap side of the rotor bars. The overall result is that t ...
... and resistance is again valid for the stator circuit of any random wound ac machine. However, the shorted bars of the rotor of an induction motor produce special problems due to deep bar effect which causes the rotor current to rise to the air gap side of the rotor bars. The overall result is that t ...
attachment=3734
... As the speed of operation is low for hydro turbines use din Hydro-electric plants, salient pole type Synchronous generators are used. These allow better ventilation and also have other advantages over smooth cylindrical type rotor. 25. Why almost all large size Synchronous machines are constructed w ...
... As the speed of operation is low for hydro turbines use din Hydro-electric plants, salient pole type Synchronous generators are used. These allow better ventilation and also have other advantages over smooth cylindrical type rotor. 25. Why almost all large size Synchronous machines are constructed w ...
DC Motors Introduction D.C. motors are seldom used in ordinary
... (ii) Half of the input power is waseted in the armature circuit. In fact, if we take into account other losses (iron and mechanical), the efficiency will be well below 50%. ...
... (ii) Half of the input power is waseted in the armature circuit. In fact, if we take into account other losses (iron and mechanical), the efficiency will be well below 50%. ...
Implementing Complex Motor Control Algorithms with a
... The sinusoidally distributed windings in the stator are similar to what would be found in a three-phase induction motor. In single phase (e.g. phase A) the number of turns of wire at any angle (α) is approximately NS cos(α). The other two phases are identical, but shifted 120 degrees. In reality, th ...
... The sinusoidally distributed windings in the stator are similar to what would be found in a three-phase induction motor. In single phase (e.g. phase A) the number of turns of wire at any angle (α) is approximately NS cos(α). The other two phases are identical, but shifted 120 degrees. In reality, th ...
Modeling and Control of a Variable-Speed Constant-Frequency Synchronous Generator With Brushless Exciter
... generator and a reduced-rating power converter, as shown in Fig. 1(b). The former offers simple configurations for generators but employs expensive power electronics converters. If a squirrel-cage induction generator is in place, it must be connected to a stable voltage source for excitation and rea ...
... generator and a reduced-rating power converter, as shown in Fig. 1(b). The former offers simple configurations for generators but employs expensive power electronics converters. If a squirrel-cage induction generator is in place, it must be connected to a stable voltage source for excitation and rea ...
Limiting short-circuit currents in medium-voltage
... In the past, when power requirements increased, the only solution was to increase the voltage in order to meet the limitations of nominal current and short-circuit current. This meant using transformers to step-up the generated voltage to 33kV or higher, and then to step the voltage back down with s ...
... In the past, when power requirements increased, the only solution was to increase the voltage in order to meet the limitations of nominal current and short-circuit current. This meant using transformers to step-up the generated voltage to 33kV or higher, and then to step the voltage back down with s ...
Commutator (electric)
![](https://commons.wikimedia.org/wiki/Special:FilePath/Universal_motor_commutator.jpg?width=300)
A commutator is the moving part of a rotary electrical switch in certain types of electric motors and electrical generators that periodically reverses the current direction between the rotor and the external circuit. It consists of a cylinder composed of multiple metal contact segments on the rotating armature of the machine. The commutator is one component of a motor; there are also two or more stationary electrical contacts called ""brushes"" made of a soft conductor like carbon press against the commutator, making sliding contact with successive segments of the commutator as it rotates. The windings (coils of wire) on the armature are connected to the commutator segments. Commutators are used in direct current (DC) machines: dynamos (DC generators) and many DC motors as well as universal motors. In a motor the commutator applies electric current to the windings. By reversing the current direction in the rotating windings each half turn, a steady rotating force (torque) is produced. In a generator the commutator picks off the current generated in the windings, reversing the direction of the current with each half turn, serving as a mechanical rectifier to convert the alternating current from the windings to unidirectional direct current in the external load circuit. The first direct current commutator-type machine, the dynamo, was built by Hippolyte Pixii in 1832, based on a suggestion by André-Marie Ampère. Commutators are relatively inefficient, and also require periodic maintenance such as brush replacement. Therefore, commutated machines are declining in use, being replaced by alternating current (AC) machines, and in recent years by brushless DC motors which use semiconductor switches.