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

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

1 Answer

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 and take current IA and IB respectively. The current IA is in phase with supply voltage V as its circuit is resistive. While IB lags V by approximately 90 as its circuit is highly inductive. The magnetic field is produced by current coil and two pressure coils, carrying less current. Hence force is exerted on coils A and B. The coil winding are arranged such that the torques on them acts in opposite direction. When both torques on coil A and B, TA and TB respectively, become equal, the moving system becomes stationary and the pointer shows steady deflection corresponding to the power factor of the load. 

by

Related questions

In a dynamometer 3-phase power factor meter, the planes of the two moving coils are at?

Last Answer : In a dynamometer 3-phase power factor meter, the planes of the two moving coils are at 120°.

What is the power factor when a single phase watt meter operating on 200 V and 5 A for 5 hours makes 2016

Description : What is the power factor when a single phase watt meter operating on 200 V and 5 A for 5 hours makes 2016 revolutions and the meter constant in revolution is 420? A) 0.04 B) 1.04 C) 0.96 D) None of these

Last Answer : What is the power factor when a single phase watt meter operating on 200 V and 5 A for 5 hours makes 2016 revolutions and the meter constant in revolution is 420? A) 0.04 B) 1.04 C) 0.96 D) None of these

In a single phase power factor meter the phase difference between the currents in the two pressure coils is?

Last Answer : In a single phase power factor meter the phase difference between the currents in the two pressure coils is exactly 90°.

The two pressure coils of a single phase power factor meter have?

Last Answer : The two pressure coils of a single phase power factor meter have the same dimensions and the same number of turns.

With neat diagram explain constructional details of dynamometer type wattmeter.

Description : With neat diagram explain constructional details of dynamometer type wattmeter.

Last Answer : Working Principle of Wattmeter: It consists of two stationary coils, called current coils and one moving coil, called voltage or potential coil. The moving coil is mounted on the spindle, in the gap ... experiences a force and tends to move in the direction as per Fleming's left hand rule. 

State the effects of errors in dynamometer type wattmeter due to i) pc- inductance ii) pc- capacitance iii) mutual inductance iv) Connection.

Description : State the effects of errors in dynamometer type wattmeter due to i) pc- inductance ii) pc- capacitance iii) mutual inductance iv) Connection.

Last Answer : Errors in wattmeter:  i) pc - inductance: Pressure coil inductance causes wattmeter to read more power than actual .  ii) pc-capacitance: The wattmeter reads less power.  iii) ... iv) Connection: In uncompensated wattmeter , the reading of wattmeter includes the powerloss in coils. 

A power factor meter has?

Last Answer : A power factor meter has one current circuit and two pressure circuits.

Draw a neat sketch of 1-ph induction type energy meter and write operating principle of it.

Description : Draw a neat sketch of 1-ph induction type energy meter and write operating principle of it. 

Last Answer : Operating Principal:- The disc is placed between the two-flux due to pressure coil and flux due to current coil, which will set up torque on the disc which is proportional to power causing the ... is proportional to voltage, the second carries a current coil so its flux is proportional to current.

The potential coil of a single phase dynamometer wattmeter has 4840 Ohm resistance. Voltage across the load is

Description : The potential coil of a single phase dynamometer wattmeter has 4840 Ohm resistance. Voltage across the load is 220 V. With the potential coil connected on the load side, the meter indicates 100 W. Approximate percentage error due to wattmeter connection is (A) 11% (B) 9% (C) 1.1% (D) 3%

Last Answer : The potential coil of a single phase dynamometer wattmeter has 4840 Ohm resistance. Voltage across the load is 220 V. With the potential coil connected on the load side, the meter indicates 100 W. Approximate percentage error due to wattmeter connection is 11%

The power factor of a single phase load can be calculated if the instruments available are?

Last Answer : The power factor of a single phase load can be calculated if the instruments available are three ammeters or three voltmeters.

In an alternator at lagging power factor the generated voltage per phase as compared to that at unity power factor?

Description : In an alternator at lagging power factor the generated voltage per phase as compared to that at unity power factor?

Last Answer : In an alternator, at lagging power factor the generated voltage per phase as compared to that at unity power factor must be more than terminal voltage.

Draw the diagram and explain the working of ferrodynamic type frequency meter.

Description : Draw the diagram and explain the working of ferrodynamic type frequency meter. 

Last Answer : Ferrodynamic type frequency meter: (Electrical resonance type frequency meter): It consists of a fixed coil. The supply whose frequency is to be measured is connected across it. This coil ... so selected that the moving coil takes up a convenient position when frequency is of normal value. 

Explain working of Weston type frequency meter.

Description : Explain working of Weston type frequency meter.

Last Answer : Weston Type Frequency Meter: There are two fixed coils marked as A and B. Each coil divided into two equal parts and are fixed such that their magnetic axis are perpendicular to each ... leading to deflections in either direction depending on the currents there in, due to changed impedances.

working of distortion factor meter with block diagram

Description : working of distortion factor meter with block diagram

Last Answer : Working : Initially the switch S is kept at position 1.The attenuator gets excluded and the bridge T network is adjusted for full suppression of fundamental frequency and hence we get ... is obtained on the meter.Thus the total rms distortion is indicated by the reading of attenuator. 

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.

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

Describe principle of operation of Doppler type ultrasonic flow meter with diagram.

Description : Describe principle of operation of Doppler type ultrasonic flow meter with diagram. 

Last Answer : Diagram: Working:  The flow meter consists of a crystal transducer mounted outside the pipe in which flow is to be measured. This transducer is a piezoelectric crystal which ... , so the frequency of the reflected wave is shifted to particle velocity, according to Doppler principle.

State the function and shape of following parts used in induction type energy meter: i) Series magnet ii) Shunt magnet iii) Al disc iv) Brake magnet

Description : State the function and shape of following parts used in induction type energy meter: i) Series magnet ii) Shunt magnet iii) Al disc iv) Brake magnet

Last Answer : i) Series magnet: produce flux proportional to current (load current) of circuit and interact in the aluminum disc with flux produced by voltage magnet for torque production. Its shape is like letter U.  ii) ... : brakes the motion of the aluminum disc or slows it down. Its shape is like letter C. 

Why energy meter is integrating type measuring instrument?

Description : Why energy meter is integrating type measuring instrument?

Last Answer : Energy Meter is Integrating Type Measuring Instrument: Energy meter is used for measurement of energy, which is obtained by integration (summation) of power supplied over the particular time duration, hence it the integrating type measuring instrument. 

List any four errors in induction type energy meter. Give method of compensation for each.

Description : List any four errors in induction type energy meter. Give method of compensation for each.

Last Answer : Errors in Induction Type Energy Meter with their Compensation:  1) Error due to friction: This error can be compensated by the additional shading band provided on the shunt electromagnet.  2) Phase ... error: This error can be compensated by providing a flux diverter' to the current magnet. 

The disc of a single phase Induction-type energy meter makes 60 revolutions in 6 minutes. Meter Constant is

Description : The disc of a single phase Induction-type energy meter makes 60 revolutions in 6 minutes. Meter Constant is 1200 rev/kWh. Power consumption in the load is (A) 1.2 kW (B) 1 kW (C) 600 W (D) 500 W

Last Answer : The disc of a single phase Induction-type energy meter makes 60 revolutions in 6 minutes. Meter Constant is 1200 rev/kWh. Power consumption in the load is 500 W

For measurement of radio frequency ac signals __________ type meter is used

Description : For measurement of radio frequency ac signals __________ type meter is used

Last Answer : For measurement of radio frequency ac signals thermo-couple type meter is used

An induction type energy meter is found to run fast. Correction for this error can be made by

Description : An induction type energy meter is found to run fast. Correction for this error can be made by  (A) Over-load compensation. (B) Voltage compensation. (C) Moving the brake magnet away from the centre of the disc. (D) Moving the brake magnet towards the centre of the disc.

Last Answer : An induction type energy meter is found to run fast. Correction for this error can be made by Moving the brake magnet away from the centre of the disc.

What type of meter is used to measure current?

Description : What type of meter is used to measure current?

Last Answer : Ammeter

Induction type single phase energy meters measure electric energy in?

Last Answer : Induction type single phase energy meters measure electric energy in kWh.

Which type of winding is used in 3 phase shell-type transformer ?

Last Answer :  Sandwich type winding is used in 3 phase shell-type transformer.

State any four errors that occur in dynamometer type wattmeter

Description : State any four errors that occur in dynamometer type wattmeter

Last Answer : Errors that occur in dynamometer type wattmeter: 1. Errors due to method of connection. 2. Error due to pressure coil inductance. 3. Error due to pressure coil Capacitance. 4. Error due to mutual ... Error due to eddy currents. 7. Temperature error. 8. Error due to vibration of moving system

Explain the “mitigation of power theft” and “faulty meter replacement” for energy conservation techniques to reduce commercial losses.

Description : Explain the “mitigation of power theft” and “faulty meter replacement” for energy conservation techniques to reduce commercial losses. 

Last Answer : Energy conservation techniques to reduce commercial losses:  1. Mitigation of Power Theft: Power theft being the most important issue which all of the service providing utilities ... agricultural sector. Prepaid meters may prove effective measures against unauthorized abstraction of energy. 

With neat sketch explain working of Weston type synchroscope.

Description : With neat sketch explain working of Weston type synchroscope.

Last Answer : Weston type synchroscope:  Working: It consists of three limbed transformer. The winding on one of the outer limbs is excited from bus- bars and that on other limb by incoming machine. The two fluxes ... the lamp is flickering at a very much slow rate and it is at its maximum brightness.

A dynamometer wattmeter can be used for?

Last Answer : A dynamometer wattmeter can be used for both D.C. and A.C.

The resistance in the circuit of the moving coil of a dynamometer wattmeter should be?

Last Answer : The resistance in the circuit of the moving coil of a dynamometer wattmeter should be high.

The power factor of a single-phase induction motor is usually?

Last Answer : The power factor of a single-phase induction motor is usually lagging.

Briefly explain how the power factor of an inductive circuit can be improved.

Description : Briefly explain how the power factor of an inductive circuit can be improved.

Last Answer : As we know that power factor should be corrected to ensure that the current supplied is cost friendly. Meaning the power factor should be around one but not greater than one(0.8-0.9) in a ... an inductive circuit due to the inductive reactance which oppose the change of current in the ac circuit. 

Why capacitors are used to improve power factor?

Description : Why capacitors are used to improve power factor?

Last Answer :  Capacitors generate reactive power instead of that drawn from source which is required by inductive loads.so it reduce the reactive current which is drawn from source to be drawn from capacitor.This control in Electric bills cost.

State the significance of power factor.

Description : State the significance of power factor.

Last Answer : Significance of power factor:-  1. Cosine of angle between voltage & current in a circuit is called power factor. 2. It is a measure of the real power in a circuit. 3. Inductive & ... KVA rating equipment 5. Greater conductor size 6. CosØ = R/Z  CosØ= Active Power/ Apparent Power 

The power factor of dielectric :

Description : The power factor of dielectric :  (A) is a function of temperature of the dielectric only (B) depends only on voltage stress to which the dielectric is stressed (C) always constant (D) both (A) and (B)

Last Answer : The power factor of dielectric :  (A) is a function of temperature of the dielectric only (B) depends only on voltage stress to which the dielectric is stressed (C) always constant (D) both (A) and (B)

The power factor of a D.C. circuit is always?

Description : The power factor of a D.C. circuit is always?

Last Answer : The power factor of a D.C. circuit is always unity.

The ratio of active power to apparent power is known as____ factor.

Description : The ratio of active power to apparent power is known as____ factor.

Last Answer : The ratio of active power to apparent power is known as power factor.

The input of an A.C. circuit having power factor of 0.8 lagging is 40 kVA The power drawn by the circuit is?

Description : The input of an A.C. circuit having power factor of 0.8 lagging is 40 kVA The power drawn by the circuit is?

Last Answer : The input of an A.C. circuit having power factor of 0.8 lagging is 40 kVA The power drawn by the circuit is 32 kW.

Power factor of electric bulb is?

Description : Power factor of electric bulb is?

Last Answer : Power factor of electric bulb is unity.

The power factor at resonance in R-L- C parallel circuit is?

Description : The power factor at resonance in R-L- C parallel circuit is?

Last Answer : since a rlc circuit at resonance behaves like a pure resistive circuit, i.e there is no phase difference between current and voltage, hence the power factor is unity.

Power factor of the system is kept high?

Description : Power factor of the system is kept high?

Last Answer : Power factor of the system is kept high to reduce line losses, to maximise the utilization of the capacities of generators, lines and transformers, to reduce voltage regulation of the line.

Power factor of an inductive circuit is usually improved by connecting capacitor to it in?

Description : Power factor of an inductive circuit is usually improved by connecting capacitor to it in?

Last Answer : Power factor of an inductive circuit is usually improved by connecting capacitor to it in parallel.

Capacitors for power factor correction are rated in?

Description : Capacitors for power factor correction are rated in?

Last Answer : Capacitors for power factor correction are rated in kVAR.

Poor power factor?

Description : Poor power factor?

Last Answer : Poor power factor reduces load handling capability of electrical system, results in more power losses in the electrical system, overloads alternators, transformers and distribution lines, results in more voltage drop in the line.

Power factor of an electrical circuit is equal to?

Description : Power factor of an electrical circuit is equal to?

Last Answer : Power factor of an electrical circuit is equal to R/Z, cosine of phase angle difference between current and voltage, kW/kVA.

What is the power factor of purely resistive circuit?

Description : What is the power factor of purely resistive circuit.

Last Answer : Unity that is 1

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

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.

The product of apparent power and cosine of the phase angle between circuit voltage and current is?

Description : The product of apparent power and cosine of the phase angle between circuit voltage and current is?

Last Answer : In parllpar reasonans RLC circuit the current is