DC motors Flashcards
1
Q
What is rotor of DC motor made of
A
Coils of wire
2
Q
What does Maxwell’s right hand rule indicate
A
Direction of magnetic field around a conductor
3
Q
What will magnetic lines of flux never do
A
Cross
4
Q
Using Fleming’s left hand rule what does each finger indicate
A
Thumb = movement
First finger = flux
Second finger = current
5
Q
What is back EMF
A
induced EMF in opposite polarity to EMF applied to conducter
6
Q
Amount of torque produced by motor Is dependent on what two things
A
Strength of magnetic field
Magnitude of armature current
7
Q
3 classifications of DC motors
A
Shunt
Series
Compound
8
Q
What must carbon brushes be fixed in same position as and why
A
Magnetic neutral axis
To stop sparking as split ring passes the brushes
9
Q
Describe armature reaction
A
Distortion of magnetic field
