PREQUIZ DC GEN N DC MOTOR

An emf is produced

• when magnetic field is static

• when the flux is proportional with the conductor

• when a conductor cuts a magnetic field.

• when conductor in phase with magnetic field

THREE FACTORS DETERMINE THE E.M.F IS GENERATED IN THE ARMATURE

• The strength of the magnetic field, (φ)

• Number of conductors armature, (Z)

• Armature speed rate, (N)

• All the above

What is the function of armature

• When armature winding is rotated using prime mover, the magnetic flux and voltage gets induced in it.

• provide mechanical support for pole

• convert a.c. to d.c.

• provides magnetic flux when field winding is excited.

This is

• shunt generator

• series generator

• short shunt generator

• long shunt generator

What is the formula for terminal voltage ,V?

This is

• Long shunt generator

• Short shunt generator

• Series generator

• Shunt generator

What is the characteristics of shunt coil?

• lower resistance and can carry large currents.

• high resistance and capable of bringing a small currents.

• high resistance and capable of bringing a higher currents.

• lower resistance and can carry small currents.

In lap winding, a=?

• a=mp

• a=2

• a=p/2

• a=2p

A four-pole generator, having lap-wound armature winding has 51 slot, each slot containing 20 conductors. What will be the voltage generated in the machine when driven at 1500 r.p.m assuming the flux per pole to be 7 mWb.

A shunt generator delivers 450A at 230V and the resistance of the shunt field and armature are 50Ω and 0.03Ωrespectively. Calculate the generated e.m.f.