The advantages of using an induction generator instead of a synchronous generator are reduced unit cost and size, ruggedness, brushless (in squirrel cage construction), absence of separate dc source, ease of maintenance, self-protection against severe overloads and short circuits, etc.
What are the advantages and disadvantages of separately excited generator over a self excited generator?
Separately excited DC generators have many advantages over self-excited DC generators. It can operate in stable condition with any field excitation and gives wide range of output voltage. The main disadvantage of these kinds of generators is that it is very expensive of providing a separate excitation source.
What are self excited generators used for?
Modern generators with field coils are usually self-excited; i.e., some of the power output from the rotor is used to power the field coils. The rotor iron retains a degree of residual magnetism when the generator is turned off.
What is self-excitation in generator?
a kind of excitation of generators where the magnetic field of the main poles is excited by a current supplied to the windings of the main poles from the armature (rotor) winding. To sustain self-excitation, the initial current must reinforce this field.
What is the difference between self excited and separately excited generator?
In a separately excited (S.E.) machine, the field winding is connected to a separate voltage source while, in a self excited generator field winding is connected across the armature terminals (provides its exciting current) .Hence, the field winding has a large number of turns with a thin conductor.
What are the advantages and disadvantages of DC motor?
DC Motor Advantages & Disadvantages
| Advantages | Disadvantages |
|---|---|
| Inexpensive controls for speed regulation | Cogging at speeds of less than 300 rpm |
| Generally a low-cost motor option | Significant power loss on full wave rectified voltage |
| Easily pairs with gear reducers | High starting torque can damage reducers |
What are the advantages of DC series motor?
Advantages of DC series motors:
- It is an easy assembly and simple design.
- Vast starting torque.
- Protection is very easy.
- It is cost-effective.
- Series wound motors can use for AC or DC supply so it is also known as universal motors.
- Compare with shunt motor DC series motor develop power for the same construction size.
What are the advantages of compound generators?
Advantages of Compound DC Generator
In compound generator, the armature voltage decreases automatically, when load current increases, due to which magnetic field produced by shunt winding decreases. But the same increase in load current flows through the series winding causes an increase in the magnetic field.
How are self-excited generators classified?
Self-excited DC generators are classified based on the field coils and their position as follows: Shunt Wound Generators. Compound Wound Generators. Series Wound Generators.
What does self exciting mean?
: excited by a current produced by the generator itself self-excited generators.
How does a self-excited AC generator work?
Shunt or Self-excited
As the generator is rotated, the stator supplies input voltage to the AVR. In addition the AVR has sensors that monitor the output of the stator. The AVR supplies power the exciter and is rectified to DC current. The current is induced onto the stator for load output.
What are the 3 types of DC motors?
There are 3 main types of DC motor that are available:- Series, Shunt and Compound. These terms relate to the type of connection of the field windings with respect to the armature circuit.
Why do we use separately excited DC generators?
A separately excited DC generator is the one whose field winding is supplied by an independent external DC source (like a battery). The magnitude of generated voltage depends upon the speed of rotation of armature and the field current, i.e., greater the speed and the field current, higher is the generated voltage.
What is the emf equation of DC generator?
As the armature rotates, a voltage is generated in its coils. In the case of a generator, the emf of rotation is called the Generated emf or Armature emf and is denoted as Er = Eg. In the case of a motor, the emf of rotation is known as Back emf or Counter emf and represented as Er = Eb.
What are the advantages of DC?
Advantages of direct current (DC)
- Increased popularity.
- Residential loads use DC.
- Wide application.
- High power quality.
- Reduced installation cost.
- Easy integration to renewables.
- No reactive power and skin effect.
- Telecommunication and data center usage.
What is the main advantage of DC motors over AC motors?
DC motors have the advantage of: higher starting torque, quick starting and stopping, reversing, variable speeds with voltage input and they are easier and cheaper to control than AC. AC motor advantages include: lower power demand on start and minimal maintenance.
What is advantage of DC shunt motor?
Advantages of Dc shunt motor:
The power supply of the DC motor is any way cheap. Shunt would motor able to runs at a predetermined speed. The speed of a dc shunt motor is sufficiently constant. Direct current machines can use for heavy industrial applications where the torque and speed wider range.
What are the advantages of Series generator?
Advantages of DC Series Motor:
While delivering high torque during an overload, the series motor draws less current and power from the source compared to a shunt or compound DC motor. The main applications where series motors are best suited are for traction applications.
What is the main disadvantage of series wound generator?
The main disadvantage of series generators, Output voltage varies as the load varies The e. mf induced in the armature winding is constant with . time Inter pole winding is connected in series with main poles of d.c machine Series motor maintains a more constant speed under varying load.
What is shunt excited generator?
generator is referred to as shunt-excited. It has the advantage of requiring no independent electrical supply. Residual magnetic flux in the iron poles produces a small generated voltage as the machine is brought up to speed. This causes a field current that increases the flux and in turn the generated
What are the essential conditions of self excitation?
There must be some residual magnetism in the field system. 2. The residual magnetism must be in proper direction. The field coils should be connected with the armature in such a way that current flowing through them should increased the emf induced by the residual magnetism.
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