Why energy meter is integrating type measuring instrument?

1 Answer

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. 

Related questions

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. 

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.

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. 

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.

Description : Describe spring control method of producing controlling torque in measuring instrument. Write any two properties required for spring material.

Last Answer : A)Spring control method: As shown in the figure, the inner ends of the both springs are attahced to the spindle, while outer end of upper spring is attached to the lever and outer ... of spring material: 1.Non Magnetic material 2.Low specific resistance 3.Low temperature coefficient of resistance

Description : Name the different torque and their function in measuring instrument.

Last Answer : List of torques in analog instruments:  1. Deflecting torque  2. Controlling / restraining torque.  3. Damping torque.  1. Deflecting torque:  - To create deflection of pointer ... .  - Bring the pointer to standstill quickly.  - To minimize oscillations about final position. 

Description : Give the classification of the errors used in measuring instrument & state the reason for their occurrence.

Last Answer : Types of errors in measuring instruments:  A) Gross error: These are due to mistakes on the part of person using the instrument.  B) Systematic Error:  i) Instrumental Error: These ... multiplying factor.  C) Random error: These persist even after gross and systematic errors are removed. 

Description : Explain magnetic effect employed in measuring instrument.

Last Answer : Magnetic Effect:  I) In PMMC meters:  ➢ When a current is passed through a conductor, magnetic field is produced round the conductor. Due to this field when current ... field it experiences a mechanical force.  Examples: Electrodynamometer type instruments, Induction type instrument. 

Description : State the function of controlling torque in electrical measuring instrument.

Last Answer : Function of controlling torque  1. The function is to opposes the deflection force and increases with the increase in the deflection of the moving system, to limit its movement. 2. and brought ... set a position where the two opposing forces i.e. deflection and controlling forces are equal. 

Description : What are the test and measuring instrument required in an Electrical depots?

Last Answer : Ans. Following are the test and measuring instruments required in an Electrical depots. a. Test lamp b. Line Tester c. Continuity tester d. Volt meter e. Ammeter f. Earth megger g. Megger h. Lux meter i. Power analyzer j. Infrared thermometer

Description : Explain the essential toques in analog type measuring instruments.

Last Answer : List of torques in analog instruments:  1. Deflecting torque  2. Controlling / Restraining torque.  3. Damping torque.  1. Deflecting torque: To create deflection proportional to ... the speed higher will be the damping torque bringing the pointer to the equilibrium position quickly. 

Description : Explain construction & working of attraction type M.I. instrument with neat diagram.

Last Answer : 1. Moving element: a small piece of soft iron in the form of a vane or rod.  2. In Attracted type a cylindrical coil or solenoid which is kept fixed. An oval-shaped soft-iron piece are ...   9. When = the pointer will be stable & we can get correct reading of the electrical quantity

Description : Write any two advantages of MI type instrument.

Last Answer : Advantages of MI Type Instrument: 1. These are robust in construction. 2. Used for both A.C. as well as D.C. measurements. 3. These are economical. 4. These possess high operating torque 5. These are simple in construction hence can be easily handled.

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.

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. 

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. 

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.

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

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

Last Answer : Ammeter

Description : Integrating or Dual Slope ADC

Last Answer : Operation: At the start of measurement the counter is reset to zero. So output of flip-flop is zero. This is applied to the switch control. The switch control now connects input voltage (Vin) to ... Then the data from counter is passed to the digital readout for display purpose.

Description : Draw a block diagram of electronic energy meter. Write function of each block.

Last Answer : Electronic Energymeter  Functions of components/blocks: - CT reduces current to reasonable value for current scaling network. - Voltage & current scaling networks reduce proportionally the voltage ... ADC converts the square wave frequency analog output to display the energy in watthour.

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.

Description : Draw and describe working of electronic energy meter.

Last Answer : working of electronic energy meter:- 1. CT reduces current to reasonable value for current scaling network. 2. Voltage & current scaling networks reduce proportionally the voltage & ... The ADC converts the square wave frequency analog output to display the energy in watthour. 

Description : What is meant by energy meter constant?

Last Answer : Energy Meter Constant  A fixed value which is used when converting meter readings to actual energy use, especially when potential transformers and similar types of equipment are used in metering. For example, K=--------rev/Kwh

Description : With neat diagram explain calibration of energy meter by direct loading method.

Last Answer : Calibration of Energy Meter by Direct Loading Method:  There are three methods for testing/calibration:  1. Long period dial test  2. Using rotary sub- standard meter  3. Using precision grade instruments  All ... of substandard meter in kWh  Then % error = [(D - DS)/DS] x 100

Description : Write any two advantages of digital energy meter.

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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

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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. 

Description : A 200 V, 5 A d.c. energy meter is tested at its marked ratings. The resistance of the pressure circuit is 8000 Ω and that of current coil is 0.1 Ω. The power consumed when testing the meter with phantom loading with current circuit excited by a 6 V battery is (A) 2.5 W (B) 5 W (C) 32.5 W (D) 35 W

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Last Answer : B

Last Answer : The adjustment of position of shading bands, in an energy meter is done to provide friction compensation.

Last Answer : The household energy meter is an integrating instrument.

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

Description : Identify the instrument that does not exist (A) Dynamo-meter type ammeter (B) Dynamo-meter type wattmeter (C) Moving-iron voltmeter (D) Moving-iron wattmeter

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Description : List three types of errors in measuring instruments. Give reasons of occurring for any one of them.

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Description : Define following terms related to measuring instruments: i) Sensitivity ii) Selectivity.

Last Answer : i) Sensitivity: It is the ratio of the change in output signal to the change in input signal of quantity being measured.  ii) Selectivity: It is the term to describe fulfillment of the requirements of measurement by an instrument to be suitable for use in a given situation. 

Description : What arc the errors occurring in measuring devices due to stray magnetic field and temp '? Explain how to compensate them.

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Description : Describe systematic errors in measuring instruments. 

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Description : Define: (i) Resolution, (ii) Calibration, with reference to electrical measuring systems.

Last Answer : Resolution The smallest increment in input (the quantity being measured) which can be detected with certainty by an instrument is called its resolution or discrimination.  OR It is ... the measuring instrument with standard instrument to find out the error in the instrument under test.

Description : List any four effects employed in measuring instruments.

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Description : Write a short note on Measuring Flask

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Description : Electrical Measuring Instruments

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Description : When measuring insulation resistance of cables using d.c. source, the galvanometer used should be initially short circuited because  (A) Cables have a low value of capacitance which draws a high ... high value of charging current (D) Cables have a low value of capacitance and initial resistance

Last Answer : When measuring insulation resistance of cables using d.c. source, the galvanometer used should be initially short circuited because Cables have a high value of capacitance which draws a high value of charging current

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Last Answer : For measuring a very high resistance we should use Meggar.