![AC motor - induction2](http://s1.studyres.com/store/data/000542979_1-d2cc4bb031ed161f459645724d1b495e-300x300.png)
AC motor - induction2
... All motors, except class D, operate at %5 slip or less at full load. • Class B (IEC Class N) motors are the default motor to use in most applications. With a starting torque of LRT = 150% to 170% of FLT, it can start most loads, without excessive starting current (LRT). Efficiency and power factor a ...
... All motors, except class D, operate at %5 slip or less at full load. • Class B (IEC Class N) motors are the default motor to use in most applications. With a starting torque of LRT = 150% to 170% of FLT, it can start most loads, without excessive starting current (LRT). Efficiency and power factor a ...
UNIT 1 - Past Papers Of Home
... At the beginning of the unit, the phenomenon of permanent magnetism and magnetic materials is dealt with and this is vital for the understanding of the topics and devices in the second half. Pupils will learn about three related magnetic effects. These are the production of a magnetic field by a cur ...
... At the beginning of the unit, the phenomenon of permanent magnetism and magnetic materials is dealt with and this is vital for the understanding of the topics and devices in the second half. Pupils will learn about three related magnetic effects. These are the production of a magnetic field by a cur ...
Experiment 6
... supplied by the source, 60 Hz in North America, and by the number of magnetic poles with which the stator is built. This speed is known as the synchronous speed and is measured in revolutions per minute, RPM. Poles always come in pairs ( a north pole and a south pole) and for a two-pole motor, the f ...
... supplied by the source, 60 Hz in North America, and by the number of magnetic poles with which the stator is built. This speed is known as the synchronous speed and is measured in revolutions per minute, RPM. Poles always come in pairs ( a north pole and a south pole) and for a two-pole motor, the f ...
Noise Reduction Techniques
... actually eliminate many of these sources of noise before they ever start. The numerous electro-mechanical devices found around every model railroad are the usual suspects when it comes to tracking down noise sources causing intermittent network problems. These include motors (found in every engine o ...
... actually eliminate many of these sources of noise before they ever start. The numerous electro-mechanical devices found around every model railroad are the usual suspects when it comes to tracking down noise sources causing intermittent network problems. These include motors (found in every engine o ...
view EM-I Question Bank
... 10M 3.Explain the principle of operation of a D.C motor.Derive the equation for the torque developed by a D.C. motor?[L2] 10M 4.a)Distinguish between generator and motor action.Derive the equation for the back e.m.f of D.C motor?[L4] 5M b).A 220V shunt motor takes 60A when running at 800 r.p.m It ha ...
... 10M 3.Explain the principle of operation of a D.C motor.Derive the equation for the torque developed by a D.C. motor?[L2] 10M 4.a)Distinguish between generator and motor action.Derive the equation for the back e.m.f of D.C motor?[L4] 5M b).A 220V shunt motor takes 60A when running at 800 r.p.m It ha ...
March 2008
... Medium Voltage Facilities Measurement and instrumentation Data acquisition and storage devices ...
... Medium Voltage Facilities Measurement and instrumentation Data acquisition and storage devices ...
- Pcpolytechnic
... the V by 900 since the main winding is highly inductive. The current flowing through the starting winding (Ist) is almost in phase with the supply voltage V as this winding is resistive. The fluxes produced due to these currents will be placed 900 with respect each other. And the resultant of th ...
... the V by 900 since the main winding is highly inductive. The current flowing through the starting winding (Ist) is almost in phase with the supply voltage V as this winding is resistive. The fluxes produced due to these currents will be placed 900 with respect each other. And the resultant of th ...
Slides on Steady-state basics
... We have established that the existence of three phase currents in the three stator windings creates a rotating magnetic field in the air gap. When the stator windings are initially energized, the rotor is stationary, and so the rotor windings see this rotating magnetic field. What happens? The rotor ...
... We have established that the existence of three phase currents in the three stator windings creates a rotating magnetic field in the air gap. When the stator windings are initially energized, the rotor is stationary, and so the rotor windings see this rotating magnetic field. What happens? The rotor ...
Unit_4_QA
... induction motor having efficiency of 88 % and full load power factor of 0.9. Assume specific magnetic loading = 0.5 wb/m2 and Specific electric loading = 25000 ac/m. The rotor peripheral speed may be approximately 20 m/sec at synchronous speed. ...
... induction motor having efficiency of 88 % and full load power factor of 0.9. Assume specific magnetic loading = 0.5 wb/m2 and Specific electric loading = 25000 ac/m. The rotor peripheral speed may be approximately 20 m/sec at synchronous speed. ...
Document
... A single phase induction motor is not self-starting; thus, it is necessary to provide a starting circuit and associated start windings to give the initial rotation in a single phase induction motor. The normal running windings within such a motor can cause the rotor to turn in either direction, so t ...
... A single phase induction motor is not self-starting; thus, it is necessary to provide a starting circuit and associated start windings to give the initial rotation in a single phase induction motor. The normal running windings within such a motor can cause the rotor to turn in either direction, so t ...
Microsoft Word - Synhronous Machines Units 5
... During the operation of the alternator, resistance voltage drop IaRa and armature leakage reactance drop IaXLare actually emf quantities and the armature reaction reactance is ammf quantity. To determine the regulation of the alternator by this method OCC, SCC and ZPF test details and characteristic ...
... During the operation of the alternator, resistance voltage drop IaRa and armature leakage reactance drop IaXLare actually emf quantities and the armature reaction reactance is ammf quantity. To determine the regulation of the alternator by this method OCC, SCC and ZPF test details and characteristic ...
Electromagnetic Induction3
... BdA If the surface is closed, then φ=∫. BdA This is because magnetic lines of force are closed lines and free magnetic poles do not exist. • Faraday’s Law: a) First Law: whenever there is a change in the magnetic flux linked with a circuit with time, an induced emf is produced in the circuit which l ...
... BdA If the surface is closed, then φ=∫. BdA This is because magnetic lines of force are closed lines and free magnetic poles do not exist. • Faraday’s Law: a) First Law: whenever there is a change in the magnetic flux linked with a circuit with time, an induced emf is produced in the circuit which l ...
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.