Electrical4U 
To determine the power extracted from wind by a wind turbine, we assume an air duct model. The wind’s velocity at the inlet is V1, and at the outlet, it’s V2. We consider that mass m of the air passes through this duct each second.Now due to this mass the kinetic energy of wind at … Read more
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
In these types of generators the field windings, armature windings and external load circuit all are connected in series as shown in figure below. Therefore, the same current flows through armature winding, field winding and the load.Let, I = Ia = Isc = ILHere, Ia = armature currentIsc = series field currentIL = load currentThere … Read more
DC generators are classified based on how their fields are excited (i.e. produced). There are three methods of excitation, and thus three main types of DC generators: Self-excited DC generators can further be classified depending on the position of their field coils. The three types of self-excited DC generators are: A portable generator is an … Read more
DC generator is that curve which gives the relation between field current and the armature terminal voltage on open circuit.When the DC generator is driven by a prime mover then an emf is induced in the armature. The generated emf in the armature is given by an expression is constant for a given machine.it is … Read more
What is a Wave Winding? A wave winding (also known as a series winding) is defined as a type of armature winding in DC machines, alongside lap winding. In a wave winding, we connect the end of one coil to the start of another coil of the same polarity. The coil side (A – B) … Read more
What is a Frog Leg Winding? A frog leg winding is a combination of a multiplex wave and a simplex lap winding in the same slots. It retains the advantages of both lap windings and wave windings without their inherent disadvantages. Lap and wave windings each have an equal number of parallel paths, which are … Read more
In shunt wound DC generators, the field windings are connected in parallel with the armature conductors. In these types of generators the armature current (Ia) splits into two parts: the shunt field current (Ish) flows through the shunt field winding, and the load current (IL) flows through the external load. Three most important characteristic of … Read more
When an alternating current flows through a coil, it creates an alternating magnetic field around it. If a second coil is placed within this magnetic field, it induces an alternating emf in the second coil due to Faraday’s law of electromagnetic induction. This emf can be used to power a load. In this setup, the … Read more
There are various types of DC generators available for several types of services. The applications of these DC generators based on their characteristic are discussed below: Applications of Separately Excited DC Generators These type of DC generators are generally more expensive than self-excited DC generators, because they need a separate excitation source. This restricts their … Read more