What is Phase sequence? Draw waveforms of 3 phase emf.

What is Phase sequence? Draw waveforms of 3 phase emf.
by

1 Answer

Answer :

Phase sequence: It is the order in which the three phases reach their peak or maximum values. It is shown in below fig. the phase sequence is A-B-C (or R-Y-B). In the following waveforms, it is seen that the R phase voltage attains the positive maximum value first, and after angular distance of 120º, Y-phase voltage attains its positive maximum and further after 120º, B- phase voltage attains its positive maximum value. So the phase sequence is R-Y-B. 

image

by

Related questions

Define phase sequence of three phase supply with waveforms.

Description : Define phase sequence of three phase supply with waveforms. What is normal phase sequence? Which 3 standard colours are used to denote the phase sequence?

Last Answer : It  is  sunnosoidal  sequence.

State the use of:- (i) Clip-on-ammeter (ii) Phase sequence indicator

Description : State the use of:- (i) Clip-on-ammeter (ii) Phase sequence indicator

Last Answer : (i) Clip-on-ammeter: used for measurement of current in cables/lines in live conditions without disconnecting them.  (ii) Phase sequence indicator: To determine /find the phase sequence of 3 phase supply. 

Describe with neat diagram phase sequence indicator.

Description : Describe with neat diagram phase sequence indicator.

Last Answer : Phase Sequence Indicator: There are two types of phase sequence indicators: (a) Rotating type phase sequence indicator (b) Static type phase sequence indicator (a) Rotating Type Phase Sequence ... of the supply is reversed or altered, then the lamp 1 will glow brighter than the lamp 2.

State the application of phase sequence indicator; clip on ammeter, frequency meter & P.F. meter.

Description : State the application of phase sequence indicator; clip on ammeter, frequency meter & P.F. meter.

Last Answer : Phase Sequence Indicator:  1. For finding correct phase sequence of supply  2. For obtaining exact instant of parallel operation of alternators.  3. For obtaining reversal of rotation ...  4. In electroplating industries   5. In various processes industries for measuring power factor

Draw the block diagram of regulated power supply, explain function of each block and draw waveforms of each stage.

Description : Draw the block diagram of regulated power supply, explain function of each block and draw waveforms of each stage.

Last Answer : 1. A step down transformer 2. A rectifier 3. A filter 4. A regulator Operation of Regulated Power Supply:- Step Down Transformer:- A step down transformer will ... regulator. A regulator will maintain the output constant even when changes at the input or any other changes occur.

State different types of electrical signal and draw all types of waveforms.

Description : State different types of electrical signal and draw all types of waveforms.

Last Answer : Types of electrical signals 1) Sine wave 2) Triangular wave 3) Square wave Waveforms

In which of the following waveforms is RMS voltage equal to the average voltage?

Description : In which of the following waveforms is RMS voltage equal to the average voltage? A) Triangle wave B) Square wave C) Sine wave D) None of these

Last Answer : In which of the following waveforms is RMS voltage equal to the average voltage? A) Triangle wave B) Square wave C) Sine wave D) None of these

Which of the following waveforms has the lowest form factor?

Description : Which of the following waveforms has the lowest form factor? A) Sine wave B) Square wave C) Sawtooth wave D) Triangle wave

Last Answer : Which of the following waveforms has the lowest form factor? A) Sine wave B) Square wave C) Sawtooth wave D) Triangle wave

The sequence components of current of a single-phase load connected to a 3-phase system are

Description : The sequence components of current of a single-phase load connected to a 3-phase system are (A) equal positive and negative sequence components (B) equal positive, negative and zero sequence components (C) vector sum of sequence currents is zero (D) algebraic sum of sequence currents is zero

Last Answer : The sequence components of current of a single-phase load connected to a 3-phase system are equal positive, negative and zero sequence components

Draw single phase full wave mid-point converter for inductive load. Draw input and output waveforms for it.

Description : Draw single phase full wave mid-point converter for inductive load. Draw input and output waveforms for it. 

Last Answer : Circuit Diagram: Waveforms:

What is back emf?

Description : What is back emf? 

Last Answer : Back EMF: When a current carrying conductor is placed in a magnetic field it experiences a force; when it moves due to the force it (conductor) cuts the magnetic field due to which an emf is ... (hence the applied armature voltage) is opposed by the induced emf which is therefore called as Back emf.

Self induced emf and Mutually induced emf

Description : Self induced emf and Mutually induced emf

Last Answer : (i) Self-induced e.m.f.: The e.m.f. induced in a coil due to the change of its own flux linked with it, is called self-induced e.m.f.  (ii) Mutually induced e.m.f.: The e.m.f. induced in a coil due to the changing current in the neighbouring coil, is called mutually induced e.m.f. 

Compare statically induced emf with dynamically induced emf on any four points.

Description : Compare statically induced emf with dynamically induced emf on any four points.

Last Answer : Statically induced emf Dynamically induced emf Emf is induced without any relative motion between conductor and magnetic field. Emf is induced due to relative motion between conductor ... induced in transformer windings e.g emf induced in Generator, Alternator armature windings

Define: 1) statically induced EMF 2) dynamically induced EMF

Description : Define: 1) statically induced EMF 2) dynamically induced EMF Write the names of equipments in which these two types of EMF get induced

Last Answer : Concept of statically induced emf: The emf induced in coil or conductors without any relative motion between it and magnetic field is called statically induced emf. When conductor is stationary and flux ... it. This emf is dynamically induced emf. e.g. Emf induced in generators, alternator.

List the two types of induced EMF.

Description : List the two types of induced EMF.

Last Answer : There are two types of EMF one is statically induced EMF and second is dynamically induced EMF.

What is the back EMF?

Description : What is the back EMF?

Last Answer : When the armature of a d.c. motor rotates under the influence of the driving torque, the armature conductors move through the magnetic field and hence e.m.f. is induced in them as in a generator. The ... that energy conversion in a d.c. motor is only possible due to the production of back emf.

A negative sequence relay is used for protection of

Description : A negative sequence relay is used for protection of  (1) Generator (3) Motor (2) Transformer (4) Long Transmission lines

Last Answer : A negative sequence relay is used for protection of Generator 

Explain dynamic and static induced emf with neat diagram.

Description : Explain dynamic and static induced emf with neat diagram.

Last Answer : Dynamically Induced EMF:-  In this case, either coil moves or magnet moves, so that there is relative motion between coil & magnetic field. Thus magnetic field is cut by coil & emf is induced in it. The emf ... The expression for induced EMF is e= -L(di/dt) or = -N(dϕ/dt).

The induced emf in the armature of a lap -wound four -pole dc machine having 100 armature conductors

Description : The induced emf in the armature of a lap -wound four -pole dc machine having 100 armature conductors rotating at 600 rpm and with 1 Wb flux per pole is  (1) 1000V (2) 100V (3) 600V (4) 10,000V

Last Answer : The induced emf in the armature of a lap -wound four -pole dc machine having 100 armature conductors rotating at 600 rpm and with 1 Wb flux per pole is 1000V

The fractional-pitch used for eliminating 7th harmonic from the emf wave of an alternator is

Description : The fractional-pitch used for eliminating 7th harmonic from the emf wave of an alternator is (A) 2/3 (B) 5/6 (C) 7/8 (D) 6/7

Last Answer : The fractional-pitch used for eliminating 7th harmonic from the emf wave of an alternator is 6/7

The back emf of synchronous motor depends on?

Description : The back emf of synchronous motor depends on?

Last Answer : The back emf of synchronous motor depends on load angle.

What is the EMF equation of the transformer?

Description : What is the EMF equation of the transformer?

Last Answer : E1 =2(3.142)fN1 (flux)1E2 =2(3.142)fN2(flux)2

Explain the principle of ON OFF control and phase control of AC voltage controller with suitable circuit and waveforms.

Description : Explain the principle of ON-OFF control and phase control of AC voltage controller with suitable circuit and waveforms.

Last Answer : The integral cycle control (on-off control) and phase angle control are the two types of AC voltage controller. The principle of ON-OFF control: The on-off control is also called an integral cycle ... control. In phase control, the switch is on for some period of each cycle.  

Draw and explain RC phase shift Oscillator.

Description : Draw and explain RC phase shift Oscillator.

Last Answer : Circuit diagram of RC phase shift oscillator: WORKING: * Circuit consists of a single stage amplifier in common emitter configuration & RC phase shifting network. * R1, R2, RE provides biasing & CE ... . * The phase shift around the loop is 3600 only at one precise frequency.  

Draw & explain operation of phase detector.

Description : Draw & explain operation of phase detector.

Last Answer : In phase detector, the op-Amp basically acts as a zero crossing detector. If a sine wave is applied at the i/p, we get square wave at the op-Amp o/p (at point ... to two channel of the CRO. The time duration between the pulses corresponding to voltages represent the phase between them. 

Give the operation of single phase full wave bridge controlled converter with RL load with a neat diagram. Also draw its waveform.

Description : Give the operation of single phase full wave bridge controlled converter with RL load with a neat diagram. Also draw its waveform.

Last Answer : Single phase fully control bridge converter with RL load: 1. During positive half cycle of input voltage, T1 and T2 are forward biased and during negative half cycle, T3 and T4 are forward biased. Therefore, T1-T2 ... cycle till the firing of next pair of SCRs as shown in the waveform.

The counter e.m.f. of a d.c. motor?

Description : The counter e.m.f. of a d.c. motor?

Last Answer : The counter e.m.f. of a d.c. motor helps in energy conversion.

E.m.f. of a Weston cell is accurately measured by?

Last Answer : E.m.f. of a Weston cell is accurately measured by electrostatic voltmeter.

It is required to measure the true open circuit e.m.f. of a battery. The best device is?

Last Answer : It is required to measure the true open circuit e.m.f. of a battery. The best device is D.C. potentiometer.

If B is the flux density, I the length of conductor and v the velocity of conductor, then induced e.m.f. is given by?

Last Answer : If B is the flux density, I the length of conductor and v the velocity of conductor, then induced e.m.f. is given by Blv.

When the armature of a D.C. motor rotates, e.m.f. induced is

Last Answer : When the armature of a D.C. motor rotates, e.m.f. induced is back e.m.f.

The mechanical power developed by a shunt motor will be maximum when the ratio of back e.m.f. to applied voltage is?

Last Answer : The mechanical power developed by a shunt motor will be maximum when the ratio of back e.m.f. to applied voltage is 0.5.

In case of D.C. shunt motors the speed is dependent on back e.m.f. only because?

Last Answer : In case of D.C. shunt motors the speed is dependent on back e.m.f. only because flux is practically constant in D:C. shunt motors.

What will happen if the back e.m.f. of a D.C. motor vanishes suddenly?

Last Answer : The armature may burn if the back e.m.f. of a D.C. motor vanishes suddenly.

Explain MCB and ELCB with connection diagram supplying single phase load.

Description : Explain MCB and ELCB with connection diagram supplying single phase load. 

Last Answer : OR OR Explanation: * MCB provides short circuit protection. * MCB provides overload protection * ELCB provides earth fault protection. * MCB is in series with ... occurs, the ELCB cuts off the power within the time of 0.1 sec. automatically to protect the personnel. 

Why is a capacitor used in a single phase motor and not in three phase motor ?

Description : Why is a capacitor used in a single phase motor and not in three phase motor ?

Last Answer : In 1-phase induction motor capacitor work is generate the auxiliary winding current than excite the main winding to rotor starts rotate. After rotor start rotating about 75% of their speed than auxiliary ... emf to start the motor.so,in 3-phase induction motor is self start induction motor.

Define Amplitude and Phase of Sinusoidal quantity.

Description : Define Amplitude and Phase of Sinusoidal quantity.

Last Answer : Amplitudes are expressed either as instantaneous values or mostly as peak values.  Amplitude is the fluctuation or displacement of a wave from its mean value.  Phase is the position of a ... .  Phase an expression of relative displacement between or among waves having the same frequency . 

working principle of single phase motor

Description : working principle of single phase motor

Last Answer : The Stator of single phase induction motor houses two windings  1. Main (Running) winding 2. Auxiliary (Starting ) winding Rotor of single phase induction motor is ... with starting winding or a capacitor may be permanently connected in series with Auxiliary (Starting ) winding.

Why is a three phase denoted by R, Y, B ?

Description : Why is a three phase denoted by R, Y, B ?

Last Answer : phase 1 ,R =Red colour cable terminal, phase 2 Y=Yellow colour terminal cable,Phase 3 B=Blue colour cable terminal, N =Neutral. For identification.

Explain the working of a single phase capacitor start induction motor.

Description : Explain the working of a single phase capacitor start induction motor. 

Last Answer : Single phase capacitor start induction motor https://youtu.be/31lvvzU5Puc

State any four advantages of three phase induction motor.

Description : State any four advantages of three phase induction motor. 

Last Answer : Advantages of three phase induction motor https://youtu.be/27OIOCKN05U

Define balanced 3 phase load.

Description : Define balanced 3 phase load.

Last Answer : Balanced 3 phase Load: Balanced three phase load is defined as star or delta connection of three equal impedances having equal real parts and equal imaginary parts. It takes same current of equal magnitude and equal phase angle.

With a neat sketch explain working of 1 phase dynamometer type power factor meter.

Description : With a neat sketch explain working of 1 phase dynamometer type power factor meter.

Last Answer : Working of 1 phase dynamometer type power factor meter : The current coil is connected in series with load. Two pressure coils marked as A and B are connected across the supply terminals ... becomes stationary and the pointer shows steady deflection corresponding to the power factor of the load. 

State the meaning of creeping error in 1 phase energy meter.

Description : State the meaning of creeping error in 1 phase energy meter.

Last Answer : Creeping error: It is defined as the slow and continuous rotation of the disc of the energy-meter when only pressure coil is energized with no current in the current coil (load current = 0). ... magnet on this iron wire is sufficient to prevent continues rotation of the disc on no load condition.

List any two methods of reactive power measurement in 3 phase circuit.

Description : List any two methods of reactive power measurement in 3 phase circuit.

Last Answer : Methods of reactive power measurement in 3 phase circuit: (i) Two single phase wattmeter method (ii) One single phase wattmeter method

Define balanced and unbalanced load in three phase circuit.

Description : Define balanced and unbalanced load in three phase circuit.

Last Answer : Balanced Load: When all the imedances of 3 phases are equal in magnitude and of same nature then load is said to be balanced.  Unbalanced Load: When all the imedances of 3 phases are not equal in magnitude and of different nature then load is said to be unbalanced.

Describe the following errors and their compensation: (i) Phase error (ii) Speed error

Description : Describe the following errors and their compensation: (i) Phase error (ii) Speed error

Last Answer : (I) Phase error   1. In the phase error the phase difference angle between ∅ & ∅ is kept by using the shading band/ring  2. If the design and location of Shading band/ring is ... of brake magnet. By changing the position of the brake magnet speed of the rotating disc can be controlled. 

State any two disadvantages of one wattmeter method of measurement of 3 phase power.

Description : State any two disadvantages of one wattmeter method of measurement of 3 phase power.

Last Answer : State any two disadvantages of one wattmeter method of measurement of 3 phase power. Disadvantages of one wattmeter method:- 1. Only used for balanced load 2. It can not be used for ... connection then neutral point must be available 4. Delta connection must be opened to connect current coil.

In an R-C phase shift oscillator, the minimum no. of R-C networks to be connected in cascade will be -

Description : In an R-C phase shift oscillator, the minimum no. of R-C networks to be connected in cascade will be -

Last Answer : In an R-C phase shift oscillator, the minimum no. of R-C networks to be connected in cascade will be 3

What is the slip (as a percentage) when a 6 pole single phase induction motor operating on 220 V and 60 Hz is

Description : What is the slip (as a percentage) when a 6 pole single phase induction motor operating on 220 V and 60 Hz is rotating at speed of 1140 rpm? A) 60% B) 5% C) 10% D) None of these

Last Answer : What is the slip (as a percentage) when a 6 pole single phase induction motor operating on 220 V and 60 Hz is rotating at speed of 1140 rpm? A) 60% B) 5% C) 10% D) None of these