Parallel Operation of DC Generators

In modern power system, power is usually supplied by many synchronous generators connected in parallel which helps to maintain continuity of plant operations. Now a day’s, isolated one large generator is outdated. When we connect two generators in parallel, they have a tendency to remain in step. By doing some changes in their armature current … Read more

Self Excited DC Generators

Modern DC generators with field coils are self-excited generators which get started with the initial current in the field coils. When generator is switched off, a small magnetism is developed in rotor iron which induced electromotive force in the armature due to which current is produced in the field windings. Initially, weak magnetic field creates … Read more

Winding Factor | Pitch Factor | Distribution Factor

Before knowing about, winding factor, we should know about pitch factor and distribution factor, since winding factor is the product of pitch factor and distribution factor. If we denote winding factor with Kw, pitch factor with Kp and distribution factor with Kd, we can write The pitch factor and distribution factor are explained below one … Read more

Hopkinson Test

Hopkinson’s Test is another useful method of testing the efficiency of a DC machine. It is a full load test and it requires two identical machines which are coupled to each other. One of these two machines is operated as a generator to supply the mechanical power to the motor and the other is operated … Read more

EMF Equation of DC Generator

The derivation of EMF equation for DC generator has two parts: Induced EMF of one conductor Induced EMF of the generator Derivation for Induced EMF of One Armature Conductor For one revolution of the conductor, Let, Φ = Flux produced by each pole in weber (Wb) and P = number of poles in the DC … Read more

Armature Winding | Pole Pitch Coil Span Commutator Pitch

Now we are going to discuss about armature winding in details. Before going through this section, we should understand some basic terms related to armature winding of DC generator. Pole Pitch Definition of Pole Pitch The pole pitch is defined as peripheral distance between center of two adjacent poles in DC machine. This distance is … Read more

Working Principle of DC Generator (Plus Diagrams)

Before we can explain the working principle of a DC generator, we need to cover the basics of generators. There are two types of generators – DC generators and AC generators. Both DC and AC generators convert mechanical power to electrical power. A DC generator produces direct power, while an AC generator produces alternating power. … Read more

Construction of DC Generator | Yoke Pole Armature Brushes of DC Generator

During explaining working principle of DC Generator, we have used a single loop DC generator. But now we will discuss about practical construction of DC Generator. A DC generator has the following parts Yoke Pole of generator Field winding Armature of DC generator Brushes of generator and Commutator Bearing Yoke of DC Generator Yoke or … Read more

Lap Winding Simplex and Duplex Lap Winding

Armature windings are mainly of two types – lap winding and wave winding. Here we are going to discuss about lap winding. Lap winding is the winding in which successive coils overlap each other. It is named “Lap” winding because it doubles or laps back with its succeeding coils. In this winding the finishing end … Read more

Characteristic of Separately Excited DC Generator

In a separately excited DC generator, the field winding is excited by an external independent source. There are generally three most important characteristic of DC generator: Magnetic or Open Circuit Characteristic of Separately Excited DC Generator The curve which gives the relation between field current (If) and the generated voltage (E0) in the armature on … Read more