Inclass9Synchronous Flashcards

1
Q

Synchronous motors are similar to induction motors in that both have stator coils that produce a rotating magnetic field.

A

T

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

IF the synchronous motor is overloaded to the point where the rotor is pulled out of step with the rotating magnetic field, no torque is developed and the OSR takes the motor off-line

A

T

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

The amortisseur winding of a synchronous motor is generally smaller than the squirrel-cage winding of a comparable induction motor because the windings is only used for starting and is not expected to dissipate heat from continous operation.

A

T

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

At approximately 95% of synchronous speed, DC excitation is applied to the wound rotor section.

A

T

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

When starting a synchornous motor, the final step is to simultaneously remove the discharge resistor from the circuit and apply the DC voltage to the field windings on the rotor.

A

T

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

An M-G set can be mounted at a remote location from the synchronous motor and cannot be used with more than one synchronous motor at a time

A

F

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

If the synchronous motor uses an AC generator mounted on the motor shaft, the generator starts providing AC power as soon as the rotor starts turning.

A

F

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

__________ windings, or damper windings, are squirrel-cage conducting bars placed in slots on the pole faces and connected at the ends.
a. Magnetic b. Wire-wound c. Amortisseur d. Field

A

c. Amortisseur

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Synchronous motors that typically run faster than about _________ are considered high-speed synchronous motors.
a. 1000mph b.450 mph c. 1000rpm d. 450rpm

A

d. 450 rpm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

When ______ are used, the rotors do not need to be excited.
a. static exciters b. permanent magnets c. brushless exciters
d. motor-generator sets

A

b. permanent magnets

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

The _________ typically is a shunt or compound wound DC generator with the armature in parallel with the shunt field and its shunt field rheostat.
a. exciter-generator b. servomotor c. motor-generator
d. slip ring

A

a. exciter generator

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

A common type of relay used with synchronous motors is a (n)_________ relay.
a. polarized field frequency b. loss of excitation(field-failure)
c. out of step d. all of the above

A

d. all of the above

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

A(n) ______________ relay is an overload relay that is used to protect a synchronous motor from damage from induced currents cause by the rotor falling out of step with the rotating stator field. a. out-of-step(OSR) b. loss-of-excitation
c. synchronous overload d. discharge

A

a. out-of-step(OSR)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

A(n)_____________ resistor is a resistor used to discharge any AC potential that builds up in the amortisseur winding of a rotor in a synchronous motor.
a. surge-arrestor b. discharge c. winding d. amortisseur

A

b. discharge

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

The type of torque that is important to understand for synchronous motors is ________ torque.
a. reluctance b. pull-in c. pull-out d. all of the above

A

d. all of the above

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

_________ torque is the maximum torque required to accelerate a synchronous motor into synchronization at the rated voltage and frequency.
a. reluctance b. Pull-out c. pull-in d. field

A

a. Reluctance

17
Q

A(n) ___________ motor is a motor that rotates at exactly the same speed as the rotating magnetic field of the stator.

A

synchronous

18
Q

A(n)______________ is a motor and a generator with shafts connected used to convert one form of power to another form of power.

A

motor generator set

19
Q

A(n)_______________ relay controls the field contactor, which will connect the field windings to the exciter and remove the discharge resistor and OSR.

A

polarized field frequency

20
Q

A(n)______________ relay is a relay used to protect a synchronous motor from damage caused by the loss of excitement in the DC winding.

A

loss of excitation

21
Q

A(n)________________ relay measures the power factor of the motor and trips the motor offline if synchronization is not achieved within the proper amount of time or if the motor pulls out of step while running.

A

field motor

22
Q

_____________ torque is torque developed by the salient rotor poles before the poles are excited by the external DC power.

A

reluctance

23
Q

_______________ torque is torque produced by a motor overload that pulls the rotor out of synchronization

A

pull-out

24
Q

A(n)_________ is a synchronous motor operated at no load in order to provide power factor correction.

A

synchronous condenser

25
Q

When a (n)___________________ motor is running at synchronous speed, there is no relative motion between the rotor and stator magnetic fields and no eddy currents are induced in the iron.

A

synchronous

26
Q

________________ are needed to shut down a synchronous motor if it slips out of synchronous speed

A

protective relay

27
Q

____________ angle is the angle between the rotor and stator fields as a synchronous motor is running under load

A

torque

28
Q

A(n)______________ power factor is a circuit with current leading voltage by some angle between 0degrees and 90degrees

A

leading

29
Q

The power factor of a synchronous motor is determined by the amount of ____________ current applied to the rotor.

A

DC excitation