Asynchronous machines

What is the main function of a motor?

• To convert mechanical energy into electrical energy

• To convert electric energy into mechanical energy

• To operate as a motor or generator, depending on the direction of energy conversion

• To convert kinetic energy into electrical energy in trains during braking.

What distinguishes direct current machines from alternating current machines?

• The direction of energy conversion

• The type of energy they convert

• The nature of the current they operate with

• The method of operation in trains.

How are the windings connected in self-excited DC machines?

• They are part of separate circuits

• They are connected as part of the same circuit.

 A machine has _________________ excitation if the fluxes of both excitation windings are added together.

• sustractive compound

• shunt

• additive compound

• serie

What type of machines are mainly used as generators?

• Independently excited machines

• Self-excited machines

• Asynchronous machines

• Synchronous machines

What is the purpose of laminating the magnetic core in rotating machines?

• To increase eddy current losses

• To reduce eddy current losses

• To increase the hysteresis losses

• To improve the inductance