Quiz sheet for three phase synchronous machines.

A synchronous motor can only run at synchronous speed because:

A) it must lock in to the RMF or it wont run at all

B) that's the speed of the RMF.

C) otherwise it will be an alternator.

D) the rotor will be damaged if it run at a slower speed.

ANSWER: A

Which of the following is NOT a method of starting a synchronous motor?

A) Shafting

B) A pony motor.

C) Amortisseur windings

D) Damper windings

ANSWER: A

Synchronous motors are called synchronous motors because:

A) They can only operate at synchronous speed.

B) They have a rotating magnetic field that is synchronous to the supply.

C) They have a prime mover that runs at synchronous speed.

D) Some smart-arse decided that the synchronous sounded cool.

ANSWER: A

To synchronize an alternator to the supply we could use the: 

A) 3 dark light method.

B) 3 bright light method.

C) 3 flashing light method

D) slapping method

ANSWER: A

V curves of a synchronous motor refer to:https://4.bp.blogspot.com/_rH0i4ey9dNE/Swq8e6SgvhI/AAAAAAAADSU/k4gtpflPL3Y/s400/Baldev+Choudhary2.jpg

A) line current and power factor depending on field excitation

B) Voltage and field excitation depending on line current

C) excitation and line current depending on voltage

D) Voltage and current depending on power factor

ANSWER: A

A reluctance motor is a type of synchronous motor that:

A) doesn't have a magnet in the rotor.

B) has a permanent magnet in the rotor

C) requires a stepping power supply

D) is reluctant to turn no matter what you do to it.

ANSWER: A

Asynchronous generation is the term used to describe: 

A) power being generated using an induction motor.

B) power being generated using a synchronous motor.

C) power being generated in a remote location.

D) a generator that consumes power.

ANSWER: A

A common method of starting modern synchronous motors is?

A) Providing a commutator.

B) Amortisseur winding.

C) The use of a compensator.

D) Star/Delta method.

ANSWER: B

A Hysteresis motor has a?

A) A rotor constructed as a smooth cylinder made of a hardened magnetic alloy.

B) Has a wound rotor.

C) Has no rotor – is solid state.

D) Has an overspeed cut out.

ANSWER: A

Amortisseur windings or ‘Damping bars’ are fitted to the rotor of a synchronous motor for:

A) Motor Starting.

B) Power factor correction.

C) Current control.

D) Voltage control.

ANSWER: A

Sudden changes in load on a synchronous motor can cause

A) Increased excitation.

B) Hunting.

C) Loose wiring connection.

D) Varying supply frequency.

ANSWER: B

Last modified: Friday, 28 May 2021, 5:28 PM