How does the flux initiate in shunt generator?

As there is small voltage is there across the terminals of DC Shunt Generator and Switch S is closed, therefore a small current will start flowing through the field circuit of DC Shunt Generator which in turn will produce magnetic flux and if the produced magnetic flux adds the residual magnetic flux then net flux will …

Where does the initial excitation of a self excited DC generator come from?

Self-excitation is made use of most often in DC generators. When a self-excited generator is started, the initial current in the field winding is produced by the electromotive force (emf) induced in the armature winding by the residual magnetic field of the main poles.

How is the field of a self excited shunt DC generator created?

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.

What energizes the magnetic fields of self excited generators?

Self-excited DC generators are generators whose field magnets are energized by the current supplied by themselves. In these type of machines, field coils are internally connected with the armature. Due to residual magnetism, some flux is always present in the poles. When the armature is rotated, some EMF is induced.

What is self-excited shunt generator?

A self-excited DC generator is the one whose field winding is excited by the current from the output of the generator itself. Depending upon the connection of field winding with the armature, the self-excited DC generators are of three types − Series Generator. Shunt Generator.

What is self excitation in DC shunt generator?

What is Self-excitation in DC shunt generator? Explanation: For a self-excited DC shunt generator field winding is connected in parallel with armature winding so that, armature current splits into load current and field current. Load current will be given out as the machine is working as a generator.

Where is a self-excited generator used?

They are generally used where the use of self-excited generators are unsatisfactory. Because of their ability of giving wide range of voltage output, they are generally used for testing purpose in the laboratories. Separately excited generators operate in a stable condition with any variation in field excitation.

What is field excitation?

The process of generating a magnetic field by means of an electric current is called excitation. Field coils yield the most flexible form of magnetic flux regulation and de-regulation, but at the expense of a flow of electric current.

What is DC shunt generator?

A shunt generator is a type of direct current electric generator in which field winding and armature winding are connected in parallel, and in which the armature supplies both the load current and the field current.

How a DC shunt generator is self protecting in nature?

Ea = KaØWm will become ideally zero and practically will reduce to very low value. Thus we observe that, in DC Shunt Generator load current reduces to zero due to collapse of terminal voltage and field current. This is why, DC Shunt Generators are self-protective to short circuit fault.

What is 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 is the self excited generator?

A self-excited DC generator is the one whose field winding is excited by the current from the output of the generator itself. Depending upon the connection of field winding with the armature, the self-excited DC generators are of three types − Series Generator.

What is a shunt connection in a generator?

The shunt connectionis in which the field is connected in parallel, or shunt with the armature. The voltage from the armature is applied directly to the field in the case of a generator, while for motoroperation the source voltage is applied to the field and armature.

How is the field flux obtained in a series connected generator?

In the series-connectedgeneratorthe field flux is obtained by passing the armature current through the series-field winding. Because the excitation is provided by the armature current, it varies widely with load, especially for a generator and therefore suffers from very poor voltage regulation.

What are self excited DC generators and how they work?

What Are Self Excited DC Generators The small amount of magnetism is present in the rotor iron. This residual magnetic field of the main poles, induced an electromotive force in the stator coils, which produces initial current in the field windings. Due to flow of small current in the coil, an increase in magnetic field occurs.

What happens when the magnetic flux changes in a loop?

If the magnetic flux through a loop of wire changes for any reason either by changing the area, A, of the loop or the field, B, through the loop Then an EMF (voltage) will be induced in the wire. This voltage will cause a current to flow (the induced current in the loop).