Working Principle of DC Generator
We can see that within the half the revolution current always flows along ABLMCD, i.e., brush no 1 up-to-date with segment a. within the following half revolution, within the figure, the direction of the induced current within the coil is reversed. But at the identical time the position of the segments a and b are reversed which ends that brush no 1 comes connected with the segment b. Hence, this within the load resistance again flows from L to M. The waveform of the current through the load circuit is as shown within the figure. This current is unidirectional.
The above content is that the essential regulation of DC generator, explained by single loop generator model. The positions of the brushes of DC generator are so as that the change over of the segments a and b from one brush to other takes place when the plane of rotating coil is at a right angle to the plane of the lines of force. it’s to become therein position, the induced EMF within the coil is zero.
Thare various forms of DC Generators available for several forms of services. The applications of these DC generators supported their characteristic are discussed below.
Applications of Separately Excited DC Generators
This type of DC generators are generally costlier than self-excited DC generators to their requirement of separate excitation source. because of that their applications are restricted. they’re generally used where the employment of self-excited generators are unsatisfactory.
- Because of their ability of giving big variety of voltage output, they’re generally used for testing purpose within the laboratories.
- Separately excited generators operate during a stable condition with any variation in field excitation. because of this property they’re used as supply source of DC Motors, whose speeds are to be controlled for various applications. Example- Ward Leonard Systems of speed control.
Applications of Shunt Wound DC Generators
The application of shunt generators is extremely much restricted for its dropping voltage characteristic. they’re used to supply power to the apparatus situated very on the brink of its position. These kind of DC generators generally give constant terminal voltage for tiny distance operation with the help of field regulators from no load to full load.
- They are used for general lighting.
- They are used to charge Battery because they’ll be made to supply constant output voltage.
- It is wont to help the Alternator increase excitement.
- They are also used for small power supply (such as a transportable generator).
Applications of Series Wound DC Generators
Uses of this sort of generator power supply are completely restricted. Because their mounting terminal is characterized by olet, it operates from load to full load. we’ll clearly see this characteristic from the graphical record of series wound generator. they supply constant current within the dropping portion of the characteristic curve . For this property they’re going to be used as constant current source and employed for various applications.
- These are wont to supply field excitation current in DC locomotives for regenerative braking.
- This forms of generators are used as boosters to compensate the drop within the feeder in various kinds of distribution systems like railway service.
- In series arc lightening this kind of generators are mainly used.
Among various types of DC generators, the compound wound DC generators are most generally used because of its compensating property. Depending upon number of series field turns, the cumulatively compounded generators could even be over compounded, flat compounded and under compounded. we’ll get desired terminal voltage by compensating the drop because of armature reaction and ohmic call in the within the road. Such generators have various applications.
- Cumulative compound wound generators are used for his or her constant voltage property for lighting, power supply purpose and heavy power services. they’re mainly remodeled compounded.
- Cumulative compound wound generators are used for driving a motor.
- For small distance operation, like power supply for hotels, offices, homes and lodges, the flat compounded generators are generally used.