🔍 Key Concepts

• Look at how many line inputs (L1, L2, L3) feed the stator and how the stator windings are connected. • Notice the separate rotor terminals (M1, M2, M3) and the external starting resistances connected to the rotor circuit. • Think about which type of motor design allows resistances to be inserted in the rotor circuit for starting and speed control.

💭 Think About

• From the diagram, is the stator supplied by single-phase or three-phase power? How can you tell? • Which motor types have a squirrel-cage rotor (no external rotor leads) versus a wound rotor (with external leads for adding resistance)? • Which option(s) describe motors where you can connect variable starting resistance in the rotor, as shown in both figure A and figure B?

✅ Before You Answer

• Verify whether there are three line conductors (L1, L2, L3) feeding the stator, indicating three-phase power. • Check if the rotor has three separate leads (M1, M2, M3) going to external resistors; this rules out a squirrel cage rotor. • Confirm that the control circuits in both A and B are designed to progressively cut out rotor resistance as the motor accelerates, a key feature of this motor type.