The speed at which an engine operates depends on the intensity of the magnetic field acting on the

12. Become a brief explanation with some animation principle of operation. Make a diagram with the parts of the rotor and the stator. Make an outline of how they are connected inductor and induced according to the type of excitation: independent, series, shunt and compound. What differences do you observe regarding generators continue? nb Described with the aid of a graphical feature-intensity speed for different connexionats.
The current motors (DC) are characterized by transforming nb electrical energy into DC receiving through terminals into mechanical energy to give to the axis. Generally these engines are very similar in terms of structure and building generators, in fact, found the change in performance is seen almost reversed. When current passes through nb the rotor of a DC motor generates a torque reaction forces created by magnetic and spin the rotor. As the switch and connections of the coils of the motor are the same as those of a conventional generator. The revolutions of the rotor induces a voltage in the coil, the voltage is opposite the outer rotor voltage. nb Because of this contrast of the two strains differ between the induced nb voltage and counter-force.
To increase the induced voltage of the device we need to accelerate the engine. The intensity is small, nb then the engine speed will remain constant as long as the death is not under load and performing mechanical work is not required for the movement of the rotor. Under load the engine turns more slowly, increasing the current intensity but reducing the induced voltage. So the engine gets more electrical power source and generates more mechanical work.
As we have previously explained the structure of a DC motor and generator also CC (dynamo) are almost identical nb but have opposite operation. We have said that the DC motors convert nb electrical energy received through the terminals into mechanical energy to give to the axis. In contrast, the DC generator converts mechanical energy received by the rotor shaft into electrical energy supplied to the network through its terminals.
To reverse the direction of rotation of a DC motor to have enough to reverse the polarity of the voltage applied to its terminals, while also varying the direction of the current flowing through its coil. This pair of forces that cause rotation become the opposite.
There is another method that involves reversing the polarity of the magnetic field produced by the excitation nb coil, but this is only possible on machines that they are accessible from the outside. Whereas in most DC motors do not have access nb to the outdoor coil is more common to use the first two methods called.
14. The problem with the boot: when to start the engine, the speed is zero and counter-force generated by the machine also; so that the intensity increases making it very damaging induced. What solutions can be taken?
Because nb the rotational speed controls the flow of current in the rotor, special devices must be used to start the engine CC. When the rotor is not moving does not really have resistance, so if we apply the normal operating voltage produces nb a current intensity that harm and create nb problems in the switch and the motor windings. To prevent this damage and keep the device in the best possible state of residence were removed using a motor connected in series, to reduce the intensity and while the engine fails to set the proper voltage induced. As the motor accelerates resistance is reduced gradually, both manually and automatically, thus solving the problems in the engine nb start and avoid any damage to its internal parts.
The speed at which an engine operates depends on the intensity of the magnetic field acting on the rotor and the current field. When the stronger the field, the lower the degree of rotation required to generate induced nb voltage large enough to resist the applied voltage. Therefore, the speed of DC motors can be controlled by varying the current in the field.
George Vittorio Sbarbaro Cahué
2014 (7) January (7) 1. Electric machines 2. Generators electric current: the ... 3. Alternating current electric generators: the alter ... 4. 5 DC motors. Movers nb AC 6. universal motors 7. Moto