Manish Kumar Saini has Published 773 Answers

Pitch Factor, Distribution Factor, and Winding Factor for Harmonic Waveforms

Manish Kumar Saini

Manish Kumar Saini

Updated on 13-Oct-2021 12:22:40

When the flux density distribution in the alternator is non-sinusoidal, the induced voltage in the winding will also be non-sinusoidal. Thus, the pitch factor or coil span factor, distribution factor and winding factor will be different for each harmonic voltage.Pitch Factor for nth HarmonicAs the electrical angle is directly proportional ... Read More

Electrical Machines – What is Synchronizing Power Coefficient?

Manish Kumar Saini

Manish Kumar Saini

Updated on 13-Oct-2021 12:19:50

When a synchronous machine is synchronised to infinite busbars, it has an inherent tendency to remain in synchronism.Rotor is accelerated – Consider an alternator delivering a steady power P at a steady load angle δ. Suppose, due to some transient disturbance, the rotor is accelerated so that the load angle ... Read More

Synchronous Generator – Construction and Working Principle

Manish Kumar Saini

Manish Kumar Saini

Updated on 01-Oct-2021 07:29:23

A synchronous generator is a synchronous machine which converts mechanical power into AC electric power through the process of electromagnetic induction.Synchronous generators are also referred to as alternators or AC generators. The term "alternator" is used since it produces AC power. It is called synchronous generator because it must be ... Read More

Short Circuit Ratio of a Synchronous Machine – Definition & Calculation

Manish Kumar Saini

Manish Kumar Saini

Updated on 01-Oct-2021 07:26:24

Short Circuit RatioThe ratio of the field current required to generate rated voltage on open-circuit to the field current required to circulate rated armature current on short circuit is called as the short-circuit ratio (SCR) of a synchronous machine.Calculation of SCRThe short circuit ratio of a synchronous machine can be ... Read More

Relationship between Speed and Frequency of Alternator

Manish Kumar Saini

Manish Kumar Saini

Updated on 01-Oct-2021 07:24:34

The frequency of the generated voltage by the alternator depends upon the number of field poles and the speed at which the field poles are rotated. One complete cycle of the voltage being generated in an armature coil when a pair of field poles i.e. one north pole and one ... Read More

Pitch Factor or Coil Span Factor in Alternator

Manish Kumar Saini

Manish Kumar Saini

Updated on 01-Oct-2021 07:22:57

Coil span or coil pitch is defined as the distance between the two sides of a coil.Pole pitch is defined as the angular distance between the central line of one pole to the central line of the next pole. A pole pitch is always 180° electrical regardless of the number ... Read More

Maximum Reactive Power for a Synchronous Generator or Alternator

Manish Kumar Saini

Manish Kumar Saini

Updated on 01-Oct-2021 07:20:39

For a salient-pole synchronous generator or alternator, the per phase reactive power is given by, $$\mathrm{𝑄_{1𝜑} =\frac{𝑉𝐸_{𝑓}}{𝑋_{𝑑}}cos\:𝛿 −\frac{𝑉^{2}}{2𝑋_{𝑑}𝑋_{𝑞}}\lbrace{(𝑋_{𝑑} + 𝑋_{𝑞} ) − (𝑋_{𝑑} − 𝑋_{𝑞})\:cos\:2\delta}\rbrace … (1)}$$Where, V is the terminal voltage per phase.Ef is the excitation voltage per phase.$\delta$ is the per phase angle between Ef and V.Xd is ... Read More

Losses and Efficiency of an Alternator

Manish Kumar Saini

Manish Kumar Saini

Updated on 30-Sep-2021 09:07:32

Losses in an AlternatorThe losses that occur in an alternator can be divided into the following categories −Copper Losses or I2R LossesThe copper losses or I2R losses occur in the armature winding and rotor winding of the alternator. These losses occur due to the resistance of the windings.$$\mathrm{Armature\:winding\:cu\:loss = {𝐼^{2}_{𝑎}} ... Read More

Hydrogen Cooling of a Synchronous Generator or Alternator

Manish Kumar Saini

Manish Kumar Saini

Updated on 30-Sep-2021 09:06:59

Hydrogen gas is used as cooling medium for cooling the alternators because of its superior cooling properties. The hydrogen cooling of the alternators requires completely seated circulated system. Mainly, oil-seated glands are used between shaft and casing of the alternator. The oil absorbs both hydrogen leaking-out and air leaking-in, so ... Read More

Excitation System of Synchronous Machine

Manish Kumar Saini

Manish Kumar Saini

Updated on 30-Sep-2021 09:05:54

Excitation in an electrical machine means production of magnetic flux by passing current in the field winding. In order to excite the field winding on the rotor of the synchronous machine the direct current is required.Excitation System in Small-size Synchronous MachinesFor small size synchronous machines (motor or generator), the direct ... Read More

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