![Chapter 9 – DC Motors and Generators](http://s1.studyres.com/store/data/014989347_1-03333a9563480e4244cc22ae781e606e-300x300.png)
Chapter 9 – DC Motors and Generators
... Referring to magnetization curve in Figure 9-4, the flux φ and EA of a dc machine is a nonlinear function of its magnetomotive force. Since the change in EA cannot be calculated analytically, the magnetization curve of the machine must be used to accurately determine its EA for a given magnetomotive ...
... Referring to magnetization curve in Figure 9-4, the flux φ and EA of a dc machine is a nonlinear function of its magnetomotive force. Since the change in EA cannot be calculated analytically, the magnetization curve of the machine must be used to accurately determine its EA for a given magnetomotive ...
ee2257 control system laboratory 0 0 3 2
... are placed on the slots and short-circuited at both ends by end rings. The diameter of the rotor is kept small in order to reduce inertia and to obtain good accelerating characteristics. The drag cup construction is employed for very low inertia applications. In this type of construction the rotor w ...
... are placed on the slots and short-circuited at both ends by end rings. The diameter of the rotor is kept small in order to reduce inertia and to obtain good accelerating characteristics. The drag cup construction is employed for very low inertia applications. In this type of construction the rotor w ...
induction-motor-notes
... But before this happen, stator poles again change their position reversing the direction of the torque exerted on the rotor. Key Point : As a result, the average torque exerted on the rotor is zero. And hence the synchronous motor is not self starting. Note : The question is obvious that will happen ...
... But before this happen, stator poles again change their position reversing the direction of the torque exerted on the rotor. Key Point : As a result, the average torque exerted on the rotor is zero. And hence the synchronous motor is not self starting. Note : The question is obvious that will happen ...
Document
... magnetic field. The field winding in a shunt motor is in parallel with the armature winding and the DC supply. If the DC line voltage is constant, the armature voltage will be constant and thus the magnetic field strength will be constant. This consistency leads to a reasonably constant speed of ope ...
... magnetic field. The field winding in a shunt motor is in parallel with the armature winding and the DC supply. If the DC line voltage is constant, the armature voltage will be constant and thus the magnetic field strength will be constant. This consistency leads to a reasonably constant speed of ope ...
B. Direct Field Oriented Control of Induction Motor
... rapidly and many commercial wind turbines in the market have capacity of 2MW or more. Also the cost of windgeneration electricity has fallen steadily. Wind turbines in USA produce about 1% of total generation [2]. Also, wind power meets 3% of the total electricity demand in Europe [3], and this deve ...
... rapidly and many commercial wind turbines in the market have capacity of 2MW or more. Also the cost of windgeneration electricity has fallen steadily. Wind turbines in USA produce about 1% of total generation [2]. Also, wind power meets 3% of the total electricity demand in Europe [3], and this deve ...
Design and Analysis of a New Dual-Stator Permanent
... power generation or in propulsion systems for electric vehicles, trains and vessels. Conventional low-speed machines are usually bulky, heavy and have low efficiency. To reduce the volume and improve the torque density, double-stator PM machines have been studied recently [1, 2]. With the stator win ...
... power generation or in propulsion systems for electric vehicles, trains and vessels. Conventional low-speed machines are usually bulky, heavy and have low efficiency. To reduce the volume and improve the torque density, double-stator PM machines have been studied recently [1, 2]. With the stator win ...
Experiment 5
... magnetic field. The field winding in a shunt motor is in parallel with the armature winding and the DC supply. If the DC line voltage is constant, the armature voltage will be constant and thus the magnetic field strength will be constant. This consistency leads to a reasonably constant speed of ope ...
... magnetic field. The field winding in a shunt motor is in parallel with the armature winding and the DC supply. If the DC line voltage is constant, the armature voltage will be constant and thus the magnetic field strength will be constant. This consistency leads to a reasonably constant speed of ope ...
For those who are quite entrenched in the vacuum industry you have
... I used to think that one had less copper than the other and the copper would act to dissipate heat. Now I understand that this is not a correct statement. But heat is certainly a factor in vacuum motors. Because most vacuum motors are only 28-35% efficient, much of the energy gets expended as heat. ...
... I used to think that one had less copper than the other and the copper would act to dissipate heat. Now I understand that this is not a correct statement. But heat is certainly a factor in vacuum motors. Because most vacuum motors are only 28-35% efficient, much of the energy gets expended as heat. ...
Solutionto QuestionBank
... I1 : load current ; I2: current through moving coil. The two fixed coils in series act as the current coil and the moving coil in series with R act as the potential coil. The moving coil is pivoted between the two fixed coils carries a current I2 proportional to V. This current is fed to m through ...
... I1 : load current ; I2: current through moving coil. The two fixed coils in series act as the current coil and the moving coil in series with R act as the potential coil. The moving coil is pivoted between the two fixed coils carries a current I2 proportional to V. This current is fed to m through ...
l-38(tb)(et) ((ee)nptel)
... practically no voltage or very small voltage due to residual field under no load condition (Ia = 0). However, field gets strengthened as load will develop rated voltage across the armature with reverse polarity, is connected and terminal voltage increases. Variation in load resistance causes the ter ...
... practically no voltage or very small voltage due to residual field under no load condition (Ia = 0). However, field gets strengthened as load will develop rated voltage across the armature with reverse polarity, is connected and terminal voltage increases. Variation in load resistance causes the ter ...
Experiment 4 - Portal UniMAP
... It is possible to change the characteristics of a separately-excited dc motor by changing the strength of the fixed magnetic field produced by the stator electromagnet. This can be carried out by changing the current that flows in the stator electromagnet. This current is usually referred to as the ...
... It is possible to change the characteristics of a separately-excited dc motor by changing the strength of the fixed magnetic field produced by the stator electromagnet. This can be carried out by changing the current that flows in the stator electromagnet. This current is usually referred to as the ...
CHAPTER 3 CAUSES AND EFFECTS OF ELECTRICAL FAULTS
... hazardous condition and steps should be taken to de-energize the motor. For lightly loaded three phase motors, say 70% of normal full load amperes, the phase current will increase by the square root of three under secondary single phase conditions. This will result the motor to draw a current of app ...
... hazardous condition and steps should be taken to de-energize the motor. For lightly loaded three phase motors, say 70% of normal full load amperes, the phase current will increase by the square root of three under secondary single phase conditions. This will result the motor to draw a current of app ...
PDF
... the machine becomes single phase. It may continue to run but requires some external means for starting, and must be massively de-rated. But in case of multi-phase machine if one phase is open circuited, it will self-start and will run with minimal de-rating. Multiphase machines are less susceptible ...
... the machine becomes single phase. It may continue to run but requires some external means for starting, and must be massively de-rated. But in case of multi-phase machine if one phase is open circuited, it will self-start and will run with minimal de-rating. Multiphase machines are less susceptible ...
eee iv semester - electrical machines ii
... among two 183 W. Determine energy magnetizing components, no load current, no load power factor , no load resistance &reactance, equivalent resistance &reactance/ph referred to primary, power factor on S.C and S.C with normal applied voltage of 400v across the stator. Stator resistance may be assume ...
... among two 183 W. Determine energy magnetizing components, no load current, no load power factor , no load resistance &reactance, equivalent resistance &reactance/ph referred to primary, power factor on S.C and S.C with normal applied voltage of 400v across the stator. Stator resistance may be assume ...
Motor - Schneider Electric
... the highest starting torque is supplied by the Full Voltage Motor starter the higher the voltage, the higher the starting torque with a full voltage motor starter the network capability to accept the inrush current needs to be verified the inrush current may generate a voltage drop at the terminals ...
... the highest starting torque is supplied by the Full Voltage Motor starter the higher the voltage, the higher the starting torque with a full voltage motor starter the network capability to accept the inrush current needs to be verified the inrush current may generate a voltage drop at the terminals ...
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.