By what means is a synchronous motor started...

🔍 Key Concepts

• How a synchronous motor develops torque only when the rotor magnetic field locks in step with the rotating stator field • Why a synchronous motor cannot normally start by itself from standstill on pure synchronous principles • Which winding type in the answer choices can act like an induction motor winding during starting

💭 Think About

• Ask yourself: Which of these options provides a way for the rotor to develop starting torque BEFORE it is synchronized with the stator field? • Which device or winding type is specifically designed so that, at low speed, the motor behaves like an induction motor, then transitions to synchronous operation as speed builds up? • Eliminate any options that are mainly used for commutation or power-factor correction rather than for producing starting torque in synchronous machines.

✅ Before You Answer

• Identify which choice refers to a winding that makes the rotor behave like a squirrel‑cage induction motor during startup. • Check which components (interpoles, compensating windings, starting capacitors, amortisseur winding) you normally associate with DC machines versus AC synchronous motors. • Verify which of these is described in your text as the usual or standard method of starting large synchronous motors and bringing them close to synchronous speed.

By what means is a synchronous motor started and brought nearly to synchronous speed?

By the use of interpoles, also known as commutating poles.

By the use of compensating windings, also known as starting windings.

By the use of starting capacitors, also known as condensers.

By the use of a squirrel-cage induction winding, also called an amortisseur winding.

🔍 Key Concepts

💭 Think About

✅ Before You Answer