Manish Kumar Saini has Published 857 Answers

Power Output of Synchronous Generator or Alternator

Manish Kumar Saini

Manish Kumar Saini

Updated on 18-Oct-2021 09:08:17

The circuit model of a cylindrical rotor synchronous generator or alternator is shown in Figure-1.Let, 𝑉 = Terminal voltage per phase$𝐸_{𝑓}$ = Excitation voltage per phase$𝐼_{𝑎}$ = Armature current$\delta$ = Load angle (between 𝑉 and $𝐸_{𝑓}$ )By applying KVL in the circuit, we get, $$\mathrm{𝑬_{𝒇} = 𝑽 + 𝑰_{𝒂}𝒁_{𝒔} … ... Read More

Power Input of Synchronous Generator or Alternator

Manish Kumar Saini

Manish Kumar Saini

Updated on 18-Oct-2021 09:06:30

The circuit model of a cylindrical rotor synchronous generator or alternator is shown in Figure-1.Let, 𝑉 = Terminal voltage per phase$𝐸_{𝑓}$ = Excitation voltage per phase$𝐼_{𝑎}$ = Armature current$\delta$ = Load angle (between 𝑉 and $𝐸_{𝑓}$ )By applying KVL in the circuit, we get, $$\mathrm{𝑬_{𝒇} = 𝑽 + 𝑰_{𝒂}𝒁_{𝒔} … ... Read More

Power Flow Transfer Equations for a Synchronous Generator

Manish Kumar Saini

Manish Kumar Saini

Updated on 18-Oct-2021 09:03:57

The circuit model of a cylindrical rotor synchronous generator is shown in Figure-1.Let, 𝑉 = Terminal voltage per phase$𝐸_{𝑓}$ = Excitation voltage per phase$𝐼_{𝑎}$ = Armature current$\delta$ = Load angle or angle between 𝑉 and $𝐸_{𝑓}$Also, the phasor diagram of the alternator at lagging power factor is shown in Figure-2.For ... Read More

Potier Triangle Method – Determining the Voltage Regulation of Alternators

Manish Kumar Saini

Manish Kumar Saini

Updated on 18-Oct-2021 09:00:37

The Potier Triangle Method is used in determining the voltage regulation of alternators. It is also known as the Zero Power Factor (ZPF) method. The following assumptions are made in the Potier triangle method −The armature reaction MMF is constant.The open-circuit characteristic (O.C.C.) taken on no-load accurately represents the relation ... Read More

Parallel Operation of Alternators

Manish Kumar Saini

Manish Kumar Saini

Updated on 14-Oct-2021 11:38:56

In practice, a very large number of 3-phase alternators operate in parallel because the various power stations are interconnected through the national grid. The electric power systems are interconnected for economy and reliable operation. This interconnection of power systems requires alternators to operate in parallel with each other.In a generating ... Read More

Load Sharing by Two Alternators in Parallel Operation

Manish Kumar Saini

Manish Kumar Saini

Updated on 14-Oct-2021 11:35:27

Consider two synchronous generators or alternators are operating in parallel and their load-frequency characteristics are shown in the figure.Let$𝑓_{1(𝑛𝑙)}$ = No load frequency of alternator 1$𝑓_{2(𝑛𝑙)}$ = No load frequency of alternator 2$𝑓_{1(𝑓𝑙)}$ = Full load frequency of alternator 1$𝑓_{2(𝑓𝑙)}$ = Full load frequency of alternator 2𝑓 = Common operating ... Read More

Slip Test on Synchronous Machine

Manish Kumar Saini

Manish Kumar Saini

Updated on 14-Oct-2021 11:33:41

The slip test is a simple no-load test, which is used to determine the direct-axis and quadrature-axis synchronous reactances of a salient-pole synchronous machine. In this test, a small voltage at rated frequency is applied to the 3-phase stator winding of the synchronous machine. The field winding is unexcited and ... Read More

Constant Flux Linkage Theorem of Synchronous Machines

Manish Kumar Saini

Manish Kumar Saini

Updated on 14-Oct-2021 11:31:19

A synchronous machine may be subjected to various disturbances. Any cause of disturbance will produce electrical and mechanical transients. These transients may result from switching, from sudden changes of load, from sudden short-circuits between line and ground or between double lines or between all the three lines. These disturbances produce ... Read More

Blondel's Two Reaction Theory of Synchronous Machines

Manish Kumar Saini

Manish Kumar Saini

Updated on 14-Oct-2021 11:30:21

Magnetic Axes of RotorThe figure shows the direct axis and the quadrature axis of a rotor −Direct AxisThe axis of symmetry of the magnetic poles of the rotor is called as direct axis or d-axis. The axis of symmetry of the north magnetic poles of the rotor is known as ... Read More

Synchronous Machine Oscillations

Manish Kumar Saini

Manish Kumar Saini

Updated on 14-Oct-2021 11:26:39

A synchronous machine under steady running conditions has a driving torque at every instant balancing its retarding torque. The retarding torque is developed by phase displacement ($\delta$) between the axis of the stator and rotor poles. A mechanical rotary system possesses inertia and restoring torque that tends to restore its ... Read More

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