Which reduced-voltage starter uses a switching arrangement to connect windings in different configurations during startup and normal operation?

Which reduced-voltage starter uses a switching arrangement to connect windings in different configurations during startup and normal operation?

• A. Autotransformer Starters
• B. Star-Delta Starters
• C. Star-Wye Starters
• D. Start-Run Starters

Answer: (B)

Star-delta starting relies on changing how the motor windings are connected as the motor goes from starting to running. At the moment of startup, the windings are wired in a star (wye) configuration. This reduces the voltage across each winding to about one third of the line voltage and lowers the starting current and torque, which helps protect the electrical supply and the motor from a heavy inrush. Once the motor reaches a sufficient speed, the connections switch to delta, so each winding now sees the full line voltage. This restores full running torque for normal operation. The key idea is the switching arrangement that reconfigures the windings from star to delta between start and run. Autotransformer starters use transformer taps to reduce voltage but don’t switch the winding configuration from star to delta. Start-Run starters and other variants don’t employ a star-to-delta switching sequence in the same explicit way. Thus, the star-delta method best fits the description of a switching arrangement that changes winding configurations during startup and normal operation.

Star-delta starting relies on changing how the motor windings are connected as the motor goes from starting to running. At the moment of startup, the windings are wired in a star (wye) configuration. This reduces the voltage across each winding to about one third of the line voltage and lowers the starting current and torque, which helps protect the electrical supply and the motor from a heavy inrush.

Once the motor reaches a sufficient speed, the connections switch to delta, so each winding now sees the full line voltage. This restores full running torque for normal operation. The key idea is the switching arrangement that reconfigures the windings from star to delta between start and run.

Autotransformer starters use transformer taps to reduce voltage but don’t switch the winding configuration from star to delta. Start-Run starters and other variants don’t employ a star-to-delta switching sequence in the same explicit way. Thus, the star-delta method best fits the description of a switching arrangement that changes winding configurations during startup and normal operation.