DC Motors: Series and Compound Motors

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What is the primary function of the field winding in a DC machine?

To provide mechanical support for the rotating armature

To produce the required magnetic field for electrical excitation (correct)

To convert electrical energy into mechanical energy

To generate the induced emf in the armature winding

Which of the following is a key difference between the operation of a DC generator and a DC motor?

The direction of current flow in the armature winding (correct)

The presence of a field winding

The construction of the rotor

The need for a commutator

A $compound$ DC motor is characterized by which of the following features?

It has a single field winding connected in parallel with the armature

It has a single field winding connected in series with the armature

It has both series and shunt field windings (correct)

It has no field windings, only a permanent magnet

Which of the following is a key application of a DC generator?

Charging batteries in electric vehicles Signup and view all the answers

What is the primary purpose of the commutator in a DC machine?

To convert the alternating current (AC) in the armature winding to direct current (DC) Signup and view all the answers

Which of the following is a key classification of DC machines?

Shunt and series Signup and view all the answers

What is the purpose of inserting a rheostat in the field winding of a DC generator?

To control the field excitation Signup and view all the answers

In a DC motor, what produces the driving force that rotates the motor?

Interaction of the magnetic field and rotor current Signup and view all the answers

What is the function of a turbine or other machine in DC generator operation?

Drive the rotor Signup and view all the answers

Which type of DC motor is typically used in applications where constant speed is required?

Shunt Motor Signup and view all the answers

What distinguishes shunt motors from compound motors in terms of speed regulation?

Shunt motors have better speed regulation than compound motors Signup and view all the answers

What are some common applications of shunt motors?

Machine tools and blowers Signup and view all the answers

In a series DC motor, what happens to the speed when the load is increased?

The speed decreases significantly due to the high starting torque Signup and view all the answers

Which type of DC motor is suitable for applications involving sudden temporary loads, such as rolling mills or heavy machine tools?

Compound DC motor Signup and view all the answers

In a 4-pole DC machine with a duplex lap winding, how many parallel paths are there for the armature winding?

8 Signup and view all the answers

If an 8-pole DC machine has a simplex wave winding for its armature, how many parallel paths would there be?

2 Signup and view all the answers

Consider a 4-pole lap-wound DC generator with 16 slots, 42 conductors per slot, running at 1800 RPM and generating 480 V. What is the value of the flux per pole if the armature winding has a total of 672 conductors?

$0.0714$ Wb Signup and view all the answers

Which of the following methods can be used to control the speed of a DC motor?

All of the above Signup and view all the answers