NEW
Font size
WorksheetsCh 4 - Electrical Machine P1
Total questions: 20
Worksheet time: 10mins
1. What are the two types of DC machines?
AC generator and DC generator
DC generator and DC motor
Stepper motor and servo motor
Induction motor and synchronous motor
2. In a generator, what is the input and output?
Electrical to mechanical
Electrical to thermal
Mechanical to magnetic
Mechanical to electrical
3. What converts AC to DC in a DC machine?
Transformer
Inverter
Commutator
Rectifier diode
4. What does a commutator do?
Converts DC to AC
Changes mechanical to heat
Converts AC to DC mechanically
Controls voltage level
5. What is used to create a magnetic field in a DC machine instead of a permanent magnet?
Battery
Solar cell
Resistor
Electromagnet
6. Where is the armature winding placed?
On rotor
On stator
On brush
On commutator
7. Which winding produces the magnetic field in a DC machine?
Armature winding
Rotor winding
Field winding
Slip ring winding
8. What type of armature connection is suitable for high voltage, low current?
Lap connection
Wave connection
Star connection
Delta connection
9. In lap connection, how many parallel paths are there for a 4-pole machine?
4
3
1
2
10. Which winding has no direct connection between field and armature?
Self-excited
Series
Shunt
Separately excited
11. What is generated when the rotor cuts magnetic flux?
Resistance
Voltage (EMF)
Capacitance
Current loss
12. What is counter EMF?
Voltage opposing the source
Voltage from battery
Voltage supporting the source
Heat energy from friction
13. What are the two main parts of a DC machine?
Brush and slip ring
Armature and shaft
Pole and winding
Stator and rotor
14. What type of DC machine uses current from the armature to excite the field?
Self-excited
Battery excited
Separately excited
Hybrid
15. In a shunt excited machine, the field winding is connected:
In series with armature
In parallel with armature
To a battery
Not connected
16. What happens to the magnetic field of an electromagnet when current stops?
It stays permanent
It becomes stronger
It reverses
It disappears
17. What is the function of brushes in a DC machine?
Reduce heat
Conduct current to and from commutator
Measure voltage
Rotate the shaft
18. What type of winding has direct connection between field and armature?
Separately excited
Self-excited
Transformer-type
External
19. What happens during commutation?
AC becomes DC
DC becomes AC
Voltage is removed
Magnetic field is reversed
20. The winding that voltage is induced in is called:
Field winding
Brush winding
Armature winding
Neutral winding
