Electrical Machines Flashcards
Why is lamination used in motors?
To reduce the effects of eddy currents
How can the output of a single loop generator be increased?
Increase field strength
Increase the speed of rotation
Add more loops to the armature and put them in series with each other.
What are the three advantages of the stationary armature configuration?
Centrifugal force is no longer an issue.
Higher speeds are possible.
Heavy duty brush gear not required.
What are the electrical characteristics of a 3 phase system?
Each phase is displaced by 120 degrees.
Each phase had the same frequency and amplitude.
What are the advantages of a three phase system?
Can produce more power than a single pase of the same size.
Less conductors required - lowers cost.
Makes self-starting induction motors possible - generates a rotating magnetic field.
Define a balanced three phase system
All phases are equal
Define an unbalanced 3 phase system
Phases are unequal
