AC MOTORS SUPPLEMENTARY

premopremo remo · 75問 · 2年前

通報

問題一覧

15. A synchronous motor can develop synchronous torque

only at synchronous speed

16. An under excited sunchronous motor takes

lagging current

A synchronous motor can be used as a synchronous capacitor when it is

over excited

A synchronous motor which works on a leading power factor and does not drive a mechanical load is called as

synchronous condenser

Which if the following motors is non self starting?

synchronous motor

Under which of the following conditions hunting of synchronous motor is likely to occur?

periodic varation of load

The maximum constant load torque under which a synchronous motor will put into synchronism at rated rotor supply voltage and frequency is known as

pull in torque

Squirrel cage induction motor differs from the slip ring type in that has no

slip rings

The shaft of induction motor is made of

carbon steel

Magnetic flux produced due to the stator winding with three phase current frequency f and which is of constant value, rotates at synchronous speed If p is the number of poles of the motor then tha synchronous speed is given by

Ns = 120 f/p

The difference between the synchronous speed Ns and the actual speed N of the rotor is known as slip. It can be expressed as a percentage and is given by

% slip S = (Ns - N)/Ns x 100

The frequency of the rotor current in an induction motor is given by (if f is the supply frequency f is the rotor frequency & S is the slip)

f = Sf

A 3 phase , 60 Hz, 60 pole induction motor has a nameplate speed of 1160 rpm, What is its slip?

3.3%

An induction motor runs at 1164 rpm. What is the percent slip?

A 3 phase induction motor is rated 50 Hp, 220 volts and 1745 rpm. What is the percent slip?

3.1%

An induction motor runs at 1440 rpm. What is the frequency of the rotor induced emf?

2 Hz

The rotor of a three phase 60 Hz, 40 pole inductor motor takes 120 kW at 3 Hz What is the synchronous speed of the induction motor?

1800 rpm

What is the speed of an induction motor of 6 poles. If the percent slip is 2.5%

1170 rpm

If thw no load speed of SCIM connected to a 3 phase 50 Hz supply is 740 rpm. The motor has

8 poles

A 3 phase 150 hp 60 Hz 460 volts 6 pole induction motor has a full load torque of 679 lb-ft. What is the full load slip?

A change of 5% in the supply voltage of a phase induction motor will produce to its torque a change of approximately

10%

The value of slip at maximum torque condition (under running condition) in terms R2 and X2 is

S = R2/X2

If the maximum torque of an induction motor is 200 kg-m at slip of 12% and the torque at 6% slip would be_________ kg-m

160

It is advisable to avoid line starting of induction motor and uses starter because

motor takes 5 to 7 times its full load current

A squirrel cage motor is started at 50% its rated voltage. What is the starting torque relative to its rated voltage starting torque

25%

An auto transformer used for starting induction and synchronous motor to reduce the current drawn from the supply lines

starting compensator

If the field of a synchronous motor is under-excited the power factor will be

lagging

Wheb the excitation of an unloaded salient pole synchronous motor suddenly gets disconnected

the motor stops

What is the average slip in percent of a synchronous motor at running speed?

The advantages of a synchronous motor over a wound rotor motor is that

the power factor may be varied

The induction motor differs from the synchronous motor is that

current is induced in its rotor

The angle between the rotor poles and stator poles in a synchronous motor is known as

torque angle

In a split phase motor, the running winding should have

low resistance and high inductance

If the capacitor of single phase motor is short circuited

The motor will not start

The starting capacitor of a single phade motor is generally

electrolytic capacitor

In a capacitor start motor the capacitor is replaced byban inductor having the same reactance as in capacitor. Then the motor will __________

not start

Which of the following is NOT a reason why single phase induction motor run?

Two windings displaced from each other

Which if the followings motor will give relatively high power factor?

Capacitor run motor

If a particular application needs high speed and hugh starting torque, then which of the following motor will be prefered?

Universal motor

The motor used fir the compressors is

Shaded pole motor

If the starting winding of a single phade induction motor is left in the circuit. it will

Drwas excessive current & overheat

If a single phase motor runs hot the probable cause cannot be

blown fuses

Direction of rotation of split phase motor can be reversed by reversing the connection of

Either Running & Starting winding only

Which of he following tyoe motor is used in electric toys

shaded pole motor

What is the instrument often used to check the degree of motor shaft alignment?

Dial indicator

DC CIRCUITS POWERLINE

DC CIRCUITS POWERLINE

75問 • 2年前

premopremo remo · 100問 · 2年前

AC CIRCUIT POWERLINE

AC CIRCUIT POWERLINE

100問 • 2年前

premopremo remo · 80問 · 2年前

DC CIRCUIT SUPPLEMENTARY PROBLEMS

DC CIRCUIT SUPPLEMENTARY PROBLEMS

80問 • 2年前

premopremo remo · 88問 · 2年前

AC CIRCUIT PASS REVIEWER

AC CIRCUIT PASS REVIEWER

88問 • 2年前

premopremo remo · 50問 · 2年前

AC CIRCUIT PART 8 PINOYBIX

AC CIRCUIT PART 8 PINOYBIX

50問 • 2年前

premopremo remo · 20問 · 2年前

AC CIRCUIT PART 1 PINOYBIX

AC CIRCUIT PART 1 PINOYBIX

20問 • 2年前

premopremo remo · 80問 · 2年前

DC MACHINES POWERLINE REVIEWER

DC MACHINES POWERLINE REVIEWER

80問 • 2年前

premopremo remo · 64問 · 2年前

AC MACHINES (ALTERNATOR) POWERLINE REVIEWER

AC MACHINES (ALTERNATOR) POWERLINE REVIEWER

64問 • 2年前

premopremo remo · 63問 · 2年前

POLYPHASE POWERLINE REVIEWER

POLYPHASE POWERLINE REVIEWER

63問 • 2年前

premopremo remo · 59問 · 2年前

AC CIRCUIT POWERLINE SUPPLY

AC CIRCUIT POWERLINE SUPPLY

59問 • 2年前

premopremo remo · 54問 · 2年前

AC MACHINES (TRANSFORMER)

AC MACHINES (TRANSFORMER)

54問 • 2年前

premopremo remo · 32問 · 2年前

CIRCUIT TRANSIENT POWERLINE

CIRCUIT TRANSIENT POWERLINE

32問 • 2年前

premopremo remo · 92問 · 2年前

POWERSYSTEM POWERLINE

POWERSYSTEM POWERLINE

92問 • 2年前

premopremo remo · 61問 · 2年前

POWERLINE REVIEWER POWERPLANT

POWERLINE REVIEWER POWERPLANT

61問 • 2年前

premopremo remo · 40問 · 2年前

POWERSYSTEM SUPPLYMENTARY

POWERSYSTEM SUPPLYMENTARY

40問 • 2年前

premopremo remo · 42問 · 2年前

ALGEBRA

ALGEBRA

42問 • 2年前

premopremo remo · 33問 · 2年前

ANALYTIC GEOMETRY

ANALYTIC GEOMETRY

33問 • 2年前

premopremo remo · 23問 · 2年前

TRIGONOMETRY

TRIGONOMETRY

23問 • 2年前

premopremo remo · 28問 · 1年前

HYDRAULICS/

HYDRAULICS/

28問 • 1年前

premopremo remo · 7問 · 1年前

STRENGTH OF MATERIALS

STRENGTH OF MATERIALS

7問 • 1年前

premopremo remo · 46問 · 1年前

ENGINEERING MECHANICS

ENGINEERING MECHANICS

46問 • 1年前

premopremo remo · 25問 · 1年前

AC MACHINES (MOTOR)

AC MACHINES (MOTOR)

25問 • 1年前

premopremo remo · 47問 · 1年前

ENGINEERING ECONOMY

ENGINEERING ECONOMY

47問 • 1年前

premopremo remo · 50問 · 1年前

THERMODYNAMICS

THERMODYNAMICS

50問 • 1年前

premopremo remo · 59問 · 1年前

APPLIED PHYSICS AND ELECTROMAGNETICS

APPLIED PHYSICS AND ELECTROMAGNETICS

59問 • 1年前

premopremo remo · 47問 · 1年前

GENERAL CHEMISTRY AND MATERIAL SCIENCE

GENERAL CHEMISTRY AND MATERIAL SCIENCE

47問 • 1年前

premopremo remo · 62問 · 1年前

PEC 2017

PEC 2017

62問 • 1年前

premopremo remo · 69問 · 1年前

ESAS 2 EVAL

ESAS 2 EVAL

69問 • 1年前

premopremo remo · 55問 · 1年前

ESAS 3 EVAL

ESAS 3 EVAL

55問 • 1年前

premopremo remo · 25問 · 1年前

ESAS 1 EVAL

ESAS 1 EVAL

25問 • 1年前

premopremo remo · 93問 · 1年前

EE1 CIRCUITS

EE1 CIRCUITS

93問 • 1年前

premopremo remo · 93問 · 1年前

EE 2 MACHINES EVAL

EE 2 MACHINES EVAL

93問 • 1年前

premopremo remo · 93問 · 1年前

PASS BOARD EXAM

PASS BOARD EXAM

93問 • 1年前

premopremo remo · 98問 · 1年前

MATH PRE BOARD POWERLINE

MATH PRE BOARD POWERLINE

98問 • 1年前

premopremo remo · 3回閲覧 · 100問 · 1年前

EE POWERLINE PREBOARD

EE POWERLINE PREBOARD

3回閲覧 • 100問 • 1年前

ESAS POWERLINE PREBOARD

ESAS POWERLINE PREBOARD

ESAS OBJECTIBE TYPES

ESAS OBJECTIBE TYPES

EE MODULE 1

EE MODULE 1

premopremo remo · 74問 · 1年前

EE MODULE 2.2

EE MODULE 2.2

74問 • 1年前

MATH MODULE 2

MATH MODULE 2

MATH MODULE 2 101

MATH MODULE 2 101

premopremo remo · 54問 · 1年前

MATH MODULE 2 102

MATH MODULE 2 102

54問 • 1年前

ESAS MODULE 1

ESAS MODULE 1

ESAS MODULE 4

ESAS MODULE 4

ESAS MODULE 4.2

ESAS MODULE 4.2

premopremo remo · 15問 · 1年前

ESAS MODULE 4.3

ESAS MODULE 4.3

15問 • 1年前

EE MODULE 3

EE MODULE 3

EE MODULE 2

EE MODULE 2

premopremo remo · 99問 · 1年前

EE REFRESHER 4

EE REFRESHER 4

99問 • 1年前

premopremo remo · 98問 · 1年前

MATH REFRESHER 4

MATH REFRESHER 4

98問 • 1年前

ESAS REFRESHER 4

ESAS REFRESHER 4

premopremo remo · 99問 · 1年前

ESAS REFRESHER 3

ESAS REFRESHER 3

99問 • 1年前

MATH FLASHING

MATH FLASHING

premopremo remo · 39問 · 1年前

MATH FLASHING 1.2

MATH FLASHING 1.2

39問 • 1年前

premopremo remo · 32問 · 1年前

MATH MULTIVECTOR

MATH MULTIVECTOR

32問 • 1年前