Unit 19. Motors and generators Flashcards
1
Q
large DC machines use stationary electromagnets called
A
Field poles
2
Q
Field poles and armature cores are made of
A
Silicon steel laminations
3
Q
DC machines use ___ to relay the power
A
Commutator
4
Q
Device used to transfer power to or from the commutator
A
Carbon brushes
5
Q
Why is carbon used for brushes
A
Low coefficient of friction, soft and wears smooth
6
Q
Two applications do DC generators
A
Portable electric welders, supply for elevator drives
7
Q
According to field arrangement, four types of DC generators are
A
Shunt wound, series wound, compound wound and separately excited
8
Q
What factor is used to control generator voltage
A
Magnetic field strength
9
Q
A manual device that regulates current flow
A
Rheostat
