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

What are the test and measuring instrument required in an Electrical depots?
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1 Answer

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
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State the function of controlling torque in electrical measuring 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. 

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

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

Name the different torque and their function in measuring instrument.

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. 

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

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. 

Explain magnetic effect employed in measuring instrument.

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. 

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Description : Why energy meter is integrating type measuring instrument?

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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.

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Description : Write a short note on Measuring Flask

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calibration and the need of calibration for measuring instruments.

Description : calibration and the need of calibration for measuring instruments.

Last Answer : Calibration - It is a process of estimating the value of a quantity by comparing that quantity with a standard quantity.    Need of calibration: - Calibration defines the accuracy and ... aim of calibration is to minimize any measurement uncertainty by ensuring the accuracy of test equipment.

Explain the essential toques in analog type measuring instruments.

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

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State two purposes of calibration of measuring instruments.

Description : State two purposes of calibration of measuring instruments.

Last Answer : Purposes of calibration of measuring instruments: - The purpose of calibration is to ensure that readings of an instrument are consistent with other instruments. It is also important in determining the ... will need to be calibrated periodically to make sure it can function properly and safely. 

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

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

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

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. 

List out any four effects of electric current used in measuring instruments & write name of meter working on it.

Description : List out any four effects of electric current used in measuring instruments & write name of meter working on it.

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

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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Describe systematic errors in measuring instruments.

Description : Describe systematic errors in measuring instruments. 

Last Answer : Systematic errors: -  ➢ Instrumental Error: These errors are caused due to the mechanical structure of measuring instrument.  a) Inherent shortcomings of instruments: Instrument may read ... or electrostatic fields.  ➢ Observational Error: Parallax errors, incorrect multiplying factor. 

List any four effects employed in measuring instruments.

Description : List any four effects employed in measuring instruments.

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When measuring insulation resistance of cables using d.c. source, the galvanometer used should be initially

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

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The desirable static characteristics of a measuring system are?

Last Answer : The desirable static characteristics of a measuring system are accuracy, sensitivity and reproducibility.

For measuring a very high resistance we should use?

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

For measuring current at high frequency we should use?

Last Answer : For measuring current at high frequency we should use thermocouple instrument.

String efficiency is used for measuring the?

Last Answer : String efficiency is used for measuring the degree of utilization of SCR.

List two advantages of PMMC instrument.

Description : List two advantages of PMMC instrument.

Last Answer : 1. It has uniform scale. 2. Power consumption is low 3. It can be obtained in wide ranges. 4. High sensitivity & accuracy 5. It is unaffected by external magnetic field. 6. Additional damping device not required. 7. Hysteresis problem is not there.

need of calibration and explain the procedure to calibrate the instrument.

Description : need of calibration and explain the procedure to calibrate the instrument.

Last Answer : Need of calibration: Every measuring device degrades over time due to normal wear and tear. These changes can be caused by various reasons such as electric or mechanical shock or a hazardous manufacturing ... different magnitude are used to calculate the resistance based on ohm's law.

feature of PMMC instrument.

Description : feature of PMMC instrument. 

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Write any four advantages of instrument transformer.

Description : Write any four advantages of instrument transformer.

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State the meaning of secondary instrument. Classify secondary instruments.

Description : State the meaning of secondary instrument. Classify secondary instruments.

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State the function of former and control spring in PMMC instrument.

Description : State the function of former and control spring in PMMC instrument.

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‘PMMC instrument is not suitable to measure AC quantity’. State the reason.

Description : ‘PMMC instrument is not suitable to measure AC quantity’. State the reason.

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Name the material used for :- (i) Moving coil (ii) Permanent magnet in PMMC instrument.

Description : Name the material used for :- (i) Moving coil (ii) Permanent magnet in PMMC instrument.

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State the meaning of absolute instrument and secondary instrument.

Description : State the meaning of absolute instrument and secondary instrument. 

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State the advantages of instrument transformer in using for extension of range of meters.

Description : State the advantages of instrument transformer in using for extension of range of meters. 

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

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

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Write any two advantages of MI type instrument.

Description : Write any two advantages of MI type instrument.

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State working principle of PMMC instrument.

Description : State working principle of PMMC instrument.

Last Answer : Working Principle of PMMC Instrument: When current carrying conductor is placed in a constant magnetic field, it experiences a force proportional to the current and produces proportional deflection torque. 

Write difference between absolute & secondary instrument.

Description : Write difference between absolute & secondary instrument.

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Compare PMMC & MI instrument.

Description : Compare PMMC & MI instrument.

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A Pyrheliometer is an instrument to measure :

Description : A Pyrheliometer is an instrument to measure :  (A) temperature of solar photovoltaic cell  (B) intensity of direct solar radiation at normal incidence  (C) intensity of indirect solar radiation  (D) efficiency of a solar photovoltaic cell

Last Answer : A Pyrheliometer is an instrument to measure : intensity of direct solar radiation at normal incidence 

In a PMMC instrument, the damping provided is :

Description : In a PMMC instrument, the damping provided is :  (A) air damping (C) eddy current damping (B) fluid damping (D) magnetic damping using a magnet

Last Answer : In a PMMC instrument, the damping provided is : eddy current damping 

The largest change of input quantity for which there is no output of instrument is called ______

Description : The largest change of input quantity for which there is no output of instrument is called ______ A) Dead time B) Dead input C) Dead output D) Dead zone

Last Answer : The largest change of input quantity for which there is no output of instrument is called Dead zone

A PMMC instrument has FSD of 100 μA and a coil resistance of 1 kΩ. To convert the instrument into an

Description : A PMMC instrument has FSD of 100 μA and a coil resistance of 1 kΩ. To convert the instrument into an ammeter with full scale deflection of 100 mA, the required shunt resistance is (A) 1 Ω (B) 1.001 Ω (C) 0.5 Ω (D) 10 Ω

Last Answer : A PMMC instrument has FSD of 100 μA and a coil resistance of 1 kΩ. To convert the instrument into an ammeter with full scale deflection of 100 mA, the required shunt resistance is 1.001 Ω

Eddy current damping cannot be used for moving iron instrument because

Description : Eddy current damping cannot be used for moving iron instrument because

Last Answer : Eddy current damping cannot be used for moving iron instrument because the presence of a permanent magnet required for such purpose would affect the deflection and hence the reading of the instrument

Identify the instrument that does not exist (A) Dynamo-meter type ammeter (B) Dynamo-meter type

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

Last Answer : 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

An instrument which detects electric current is known as?

Description : An instrument which detects electric current is known as?

Last Answer : An instrument which detects electric current is known as galvanometer.

Instrument transformers are?

Last Answer : Instrument transformers are potential transformers, current transformers.

The rectifier instrument is not free from?

Last Answer : The rectifier instrument is not free from frequency error.

A multirange instrument has?

Last Answer : A multirange instrument has multiple shunt or series resistances inside the meter.

The gravity controlled instrument has crowded scale because current is proportional to?

Last Answer : The gravity controlled instrument has crowded scale because current is proportional to sine of deflection angle.

If an instrument has cramped scale for larger values, then it follows?

Last Answer : If an instrument has cramped scale for larger values, then it follows logarithmic law.