MEDIUM
Earn 100

What is a stator in alternator?

Important Questions on Electromagnetic Induction and Alternating Current

EASY

In a.c. generator induced emf at t=0. the induced emf at the time πω is_____________.

MEDIUM
What is Dynamo? Draw a labelled diagram and describe the working of an AC dynamo.
EASY

What is a dynamo? Describe an a.c. dynamo under the following headings:

ii Labelled diagram

MEDIUM

With the help of a labelled diagram, derive the expression for instantaneous emf induced in an AC generator.

HARD

The phenomenon of electromagnetic induction has been technologically important application in the generation of alternating currents." Name the device which can generate alternating currents. Draw a neat diagram of it.

 A rectangular coil having an area vector A¯ and number of turns N is rotating in a magnetic field B¯ with angular speed ω. If θbe the angle made by the area vector A¯ with the field B¯ at time t. Derive an expression for alternating emf ε starting directly from Faraday's law. Draw a graph to show the generated e.m.f at the time   0 ,T4.T2,3T4and T.

EASY

What is a dynamo? Describe an a.c. dynamo under the following headings:

iii Working.

MEDIUM
At which position of the plane of the rotating coil with the direction of magnetic field, the e.m.f. induced in the coil is maximum?
MEDIUM
The relation in root-mean-square value irms and peak value i0 of alternating current is-
EASY
An AC generator consists of a coil of 100 turns and is of cross-sectional area 3 m2. It is rotating at a constant angular speed of 60 rad s-1 in a uniform magnetic field of 0.04 T. Resistance of the coil is 360 Ω. What is the maximum power dissipation in the coil?
EASY
a 50 Hz, 3-phase synchronous generator has inductance per phase of 15 mH. The capacitance of the generator and circuit breaker is 0.002 µF. What is its natural frequency?
MEDIUM

Which type of electrical braking is preferred in industries?

EASY
A 4 pole DC generator is running at 1500 rpm the frequency of current in the armature winding is _____.
EASY
At time t=0 s, voltage of an A.C. Generator starts from 0 V and becomes 2 V at time t=1100π second. The voltage keeps on increasing up 100 V, after which it starts to decrease. Find the frequency of the Generator.
MEDIUM

Represent the union of two sets by Venn diagram for each of the following.

X={x | x is a prime number between 80 and 100}

Y={y | y is an odd number between 90 and 100}

EASY
What will the load angle be if the mechanical input is increased with constant excitation in a synchronous generator?
EASY
In an AC generator, a coil with N turns, all of the same area A and total resistance R, rotates with angular frequency ω in a magnetic field B. The maximum value of emf generated in the coil is