Wound Rotors

What are components of a WRIM?

Rotor
Slip rings
Brushes
Resistors

What are advantages of a WRIM?

Best starting (high rotor resistance and low rotor inductance)
Best running (low rotor resistance and low rotor inductance)

What are disadvantages of a WRIM?

Higher cost.
Larger frame.
Auxiliary equipment needed.
More maintenance.

What are the limitations of using resistors for speed control?

As resistance increases, slip and %reg increase.
Efficiency at lower speed decreases.
Only practical between half load and full load because torque in unstable at lower speeds.