Exam Details
| Subject | Electrical Measurements And Instruments | |
| Paper | ||
| Exam / Course | Diploma -VIEP-Electrical Engineering (DELVI)/Advanced Level Certificate Course In Electrical Engineering (ACELVI) | |
| Department | School of Engineering & Technology (SOET) | |
| Organization | indira gandhi national open university | |
| Position | ||
| Exam Date | June, 2015 | |
| City, State | new delhi, |
Question Paper
1. Choose the best option given in the following questions.
When measured value approaches the mean value, the reading is
Accurate, but not Precise
Precise but not Accurate
Precise
Both Accurate and Precise
In a measurement system, if measured quantity is across variable and is through variable, then the admittance may be given as
x. Y
x/y
y/x
x
In an electrodynamometer type instrument, deflection is proportional to
self-inductance of the moving coil and fixed coil
derivative of the self-inductance of the fixed coil
the galvanometer constant
currents in the moving coil and fixed coil
In two-wattmeter method of power measurement at 0·5 p.f.,
both the wattmeters read same in magnitude and direction
both the wattmeters read same in opposite direction
one wattmeter reads zero
total power measured is slightly less than the power consumed by 50%
A three-phase, three-wire energy meter generally contains
three pressure coils and two current coils
two current coils and one pressure coil
one current coil and two pressure coils
two current coils and two pressure coils
A Lissajous pattern of circle means that the two applied inputs are
in phase and of same amplitude
out of phase by 30° and of same amplitude
out of phase by 60° and of same amplitude
out of phase by 90° and of same amplitude
Which of the following is not true?
A PMMC, MI or Electrodynamometer type instrument can measure physical units in DC.
An MI, Induction type or Electrodynamometer type instrument can measure physical units in AC.
An Electrostatic type, Thermocouple type or Rectifier type instrument can measure physical units in AC and DC.
An MI, Induction type or Electrostatic type instrument can measure physical units in DC.
Write down your understanding of loading effect due to shunt connected instruments. Draw the schematic diagram and derive the expression for measured voltage.
Consider the following figure:
<img src='./qimages/15574-2b.jpg'>
A 50 V voltmeter with internal resistance 1000 k.ohm is connected across 200 k.ohm resistor to measure voltage across it. Determine the following:
Actual voltage across 200 k.Q resistor
Measured voltage across 200 k.ohm
Accuracy in measurement
Discuss the construction and working of permanent magnet moving coil type instrument with the help of a neat sketch.
Describe the construction and explain the principle of operation of the moving iron type instrument.
Explain the construction and working of a single phase induction type energy meter.
What do you mean by creeping in energy meters? How can this error be reduced?
5. The power flowing in a 3-phase 3-wire balanced load system is measured by two-wattmeter method. Reading of wattmeter is 7500 W and that of wattmeter is -1500 W. Determine the following
Power factor of the system
If the voltage of the circuit is 400 what is the value of the capacitance which must be introduced in each phase-to cause the whole of the power measured to appear on wattmeter A Supply frequency is 50 Hz.
Explain the vertical and horizontal deflection system of a CRT.
Describe the construction and working principle of a megger.
7. Write short notes on any two of the following
Essential Torques m an Indicating Instrument
Digital Multimeter
Maximum Demand Indicator
When measured value approaches the mean value, the reading is
Accurate, but not Precise
Precise but not Accurate
Precise
Both Accurate and Precise
In a measurement system, if measured quantity is across variable and is through variable, then the admittance may be given as
x. Y
x/y
y/x
x
In an electrodynamometer type instrument, deflection is proportional to
self-inductance of the moving coil and fixed coil
derivative of the self-inductance of the fixed coil
the galvanometer constant
currents in the moving coil and fixed coil
In two-wattmeter method of power measurement at 0·5 p.f.,
both the wattmeters read same in magnitude and direction
both the wattmeters read same in opposite direction
one wattmeter reads zero
total power measured is slightly less than the power consumed by 50%
A three-phase, three-wire energy meter generally contains
three pressure coils and two current coils
two current coils and one pressure coil
one current coil and two pressure coils
two current coils and two pressure coils
A Lissajous pattern of circle means that the two applied inputs are
in phase and of same amplitude
out of phase by 30° and of same amplitude
out of phase by 60° and of same amplitude
out of phase by 90° and of same amplitude
Which of the following is not true?
A PMMC, MI or Electrodynamometer type instrument can measure physical units in DC.
An MI, Induction type or Electrodynamometer type instrument can measure physical units in AC.
An Electrostatic type, Thermocouple type or Rectifier type instrument can measure physical units in AC and DC.
An MI, Induction type or Electrostatic type instrument can measure physical units in DC.
Write down your understanding of loading effect due to shunt connected instruments. Draw the schematic diagram and derive the expression for measured voltage.
Consider the following figure:
<img src='./qimages/15574-2b.jpg'>
A 50 V voltmeter with internal resistance 1000 k.ohm is connected across 200 k.ohm resistor to measure voltage across it. Determine the following:
Actual voltage across 200 k.Q resistor
Measured voltage across 200 k.ohm
Accuracy in measurement
Discuss the construction and working of permanent magnet moving coil type instrument with the help of a neat sketch.
Describe the construction and explain the principle of operation of the moving iron type instrument.
Explain the construction and working of a single phase induction type energy meter.
What do you mean by creeping in energy meters? How can this error be reduced?
5. The power flowing in a 3-phase 3-wire balanced load system is measured by two-wattmeter method. Reading of wattmeter is 7500 W and that of wattmeter is -1500 W. Determine the following
Power factor of the system
If the voltage of the circuit is 400 what is the value of the capacitance which must be introduced in each phase-to cause the whole of the power measured to appear on wattmeter A Supply frequency is 50 Hz.
Explain the vertical and horizontal deflection system of a CRT.
Describe the construction and working principle of a megger.
7. Write short notes on any two of the following
Essential Torques m an Indicating Instrument
Digital Multimeter
Maximum Demand Indicator
Other Question Papers
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- Basics of Electrical Engineering
- C - Programming
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