![motors and generators](http://s1.studyres.com/store/data/007898721_1-e8a148abcf8bfc06548c2b02d3de630c-300x300.png)
Exam 3 Practice
... reactance of j1.0 ohms per phase. Assume the armature resistance (Ra) is zero. The field current is set to produce a terminal voltage of 480V (line–line) at full load. At full load the machine supplies 60 amps at 1.0 power factor. a)(1) Sketch the per phase equivalent circuit showing the field and a ...
... reactance of j1.0 ohms per phase. Assume the armature resistance (Ra) is zero. The field current is set to produce a terminal voltage of 480V (line–line) at full load. At full load the machine supplies 60 amps at 1.0 power factor. a)(1) Sketch the per phase equivalent circuit showing the field and a ...
What Drives Electric Multiple Units?
... driven by electric motors powered by current collected through pantographs on the top of the car. The entire mechanism can be explained from the viewpoint of how current flows and drives the motors. Figure 1 shows a concept of the main equipment installed on an inverter-controlled EMU and a circuit ...
... driven by electric motors powered by current collected through pantographs on the top of the car. The entire mechanism can be explained from the viewpoint of how current flows and drives the motors. Figure 1 shows a concept of the main equipment installed on an inverter-controlled EMU and a circuit ...
parametric study of rotor slot shape on a cage induction motor
... Parameterisation of the rotor slot The parameterisation of the rotor slot is based on the previous slot shape shown in Fig.1. The chosen geometric parameters are: the radius r1, r2 and r3, the width w1, and the depths d1, d2 and d3. The authors have adopted a compromise between the need to optimise ...
... Parameterisation of the rotor slot The parameterisation of the rotor slot is based on the previous slot shape shown in Fig.1. The chosen geometric parameters are: the radius r1, r2 and r3, the width w1, and the depths d1, d2 and d3. The authors have adopted a compromise between the need to optimise ...
2014
... 5. a) Two shunt generators operating in parallel deliver a total current of 250 A. One of the generators is rated 50 kW and the other 100 kW. The voltage ratings of the both the machines is 500 V and have regulations of 6% (smaller one) and 4%. Assuming linear characteristics, determine i) the curre ...
... 5. a) Two shunt generators operating in parallel deliver a total current of 250 A. One of the generators is rated 50 kW and the other 100 kW. The voltage ratings of the both the machines is 500 V and have regulations of 6% (smaller one) and 4%. Assuming linear characteristics, determine i) the curre ...
Chapter DC machines and universal motors
... done in several ways, as will be discussed in the next section. Here, for simplicity sake, an DC source that is totally independent from the armature circuit is considered. In the lower part of the figure, instead, motor operation is considered. The armature is to be connected to a DC source, and so ...
... done in several ways, as will be discussed in the next section. Here, for simplicity sake, an DC source that is totally independent from the armature circuit is considered. In the lower part of the figure, instead, motor operation is considered. The armature is to be connected to a DC source, and so ...
Chapter 16
... • A separately-excited generator is less impacted by load changes than a selfexcited generator • Armature current affects the voltage ...
... • A separately-excited generator is less impacted by load changes than a selfexcited generator • Armature current affects the voltage ...
edc-module_ia-dc_generator
... 1. Brushes must be shifted to the new position of the MNA 2. Extra turns in the field winding 3. Slots are made on the tips to increase the reluctance 4. The laminated cores of the shoe are staggered 5. In big machines the compensating winding at pole shoes produces a flux which just opposes the arm ...
... 1. Brushes must be shifted to the new position of the MNA 2. Extra turns in the field winding 3. Slots are made on the tips to increase the reluctance 4. The laminated cores of the shoe are staggered 5. In big machines the compensating winding at pole shoes produces a flux which just opposes the arm ...
9. Speed control of DC shunt motor
... it. (i.e.,, is directly proportional to Ish & Ish= V/Rsh). When a variable resistance R is connected in series with the shunt field winding as shown in fig. (1), the shunt field current (Ish = V/(Rsh+R)) is reduced & hence the flux Ø. Consequently, the motor runs at a speed higher than the normal sp ...
... it. (i.e.,, is directly proportional to Ish & Ish= V/Rsh). When a variable resistance R is connected in series with the shunt field winding as shown in fig. (1), the shunt field current (Ish = V/(Rsh+R)) is reduced & hence the flux Ø. Consequently, the motor runs at a speed higher than the normal sp ...
Chapter 36 Summary – Magnetism
... Directions: write the word or phrase from the word bank in the blank below that correctly describes the idea. Word Bank: magnetic poles, like, current, voltmeter, magnetic domains, galvanometer, magnetic field lines, magnetism, repel, permanent magnet, opposite, electromagnet, magnetic field, altern ...
... Directions: write the word or phrase from the word bank in the blank below that correctly describes the idea. Word Bank: magnetic poles, like, current, voltmeter, magnetic domains, galvanometer, magnetic field lines, magnetism, repel, permanent magnet, opposite, electromagnet, magnetic field, altern ...
Modern Drive Technology
... are areas where AC motors excel and areas where DC motors hold a clear advantage. An AC motor's long life, limited only by the slow wearing of its bearings, offers a distinct advantage over the changing of brushes. However, DC motors are better in areas of high starting torque, slow speed operation, ...
... are areas where AC motors excel and areas where DC motors hold a clear advantage. An AC motor's long life, limited only by the slow wearing of its bearings, offers a distinct advantage over the changing of brushes. However, DC motors are better in areas of high starting torque, slow speed operation, ...
(Induction) Machines
... molded in the slots instead of a winding. ■ Two rings short circuits the bars.–Most of single phase induction motors have Squirrel-Cage rotor. ■ One or 2 fans are attached to the shaft in the sides of rotor to cool the circuit. ...
... molded in the slots instead of a winding. ■ Two rings short circuits the bars.–Most of single phase induction motors have Squirrel-Cage rotor. ■ One or 2 fans are attached to the shaft in the sides of rotor to cool the circuit. ...
IM - Module 5
... In principle, a switched-reluctance motor operates like a variablereluctance step motor discussed in the previous section. However, the operation differs mainly in the complicated control mechanism of the motor. In order to develop torque in the motor, the rotor position should be determined by sens ...
... In principle, a switched-reluctance motor operates like a variablereluctance step motor discussed in the previous section. However, the operation differs mainly in the complicated control mechanism of the motor. In order to develop torque in the motor, the rotor position should be determined by sens ...
RB-Pol-266 200:1 Plastic Gearmotor 90 Degree Shaft
... operating voltage range for this motor is 3 - 12V. This is a higher-torque, lower-speed version of the 120:1 plastic gearmotor 90-degree output. At 6V, the gearbox and motor provide approximately 100 oz-in of torque and 51 RPM. The free-running current is 70mA, and the stall current is 800 mA. The g ...
... operating voltage range for this motor is 3 - 12V. This is a higher-torque, lower-speed version of the 120:1 plastic gearmotor 90-degree output. At 6V, the gearbox and motor provide approximately 100 oz-in of torque and 51 RPM. The free-running current is 70mA, and the stall current is 800 mA. The g ...
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.