Basic Structure of a DC Machine

Question 1

dc machine def

Answer 1

electromechanical device that either converts mech energy to direct current (DC geenerator) or converts DC electrical energy into mechanical energy (DC motor)

Question 2

2 parts of dc machine

Answer 2

armature
field windings

Question 3

what is armature

Answer 3

This is where electrical energy is converted to mechanical energy (in motors) or vice versa (in generators).

The armature winding carries current, and when it moves through a magnetic field, it experiences a force (as per Lorentz Force Law), producing torque.

This torque turns the rotor, which can drive a mechanical load (like a fan or wheel).

Question 4

what is field winding

Answer 4

set of circuits or components such as a permanent magnet/electromagnets to produce flux (magnetic field) for the machine

Question 5

what is the function and commutator in a DC machine

Answer 5

as armature rotates, armature conductors rotate move through the magnetic lines, and this means current direction changes too

commutator = cylinder shaped copper ring that rotates with the rotor, allows for reverse of current direction through the windings or else the force (torque) would flip every half turn instead of spinning (only 180 instead of 360)

ensures that torque remains consistent or it would jerk

Question 6

what are brushes

Answer 6

brushes = connect the rotating armature to the external circuit, provides path of current to flow between power source and armature windings

Question 7

what is rated V and I of the machine

Answer 7

the V and I that the machine is designed for, maximum value before unsafe operation

Question 8

how to get rated torque of machine

Answer 8

achieve rated speed and mechanical power

Question 9

how does size of load affect rated torque

Answer 9

needs to be matched to the load, if the size of load goes over the machine might not operate