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Answer :

In a moving iron meter, the deflecting torque is proportional to Square of the current through the coil.

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Last Answer :  In a moving coil instrument, the deflecting torque is proportional to Current.

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Last Answer : In the case of PMMC rectifier type instruments, the deflecting torque is proportional to Average value of AC current.

Description : When both deflecting and controlling torque act, the pointer of an indicating instrument comes to

Last Answer : rest

Description : If the pointer of an indicating instrument is in motion, then what opposes deflecting torque?

Last Answer : damping and controlling torque

Description : The torque produced in wattmeter is proportional to

Last Answer : A

Description : The meter which does not have any component in it to provide control torque is (A) Electrodynamometer for current measurement (B) Electrodynamometer for voltage measurement (C) Electrodynamometer for power measurement. (D) Electrodynamometer for power factor measurement.

Last Answer : The meter which does not have any component in it to provide control torque is Electrodynamometer for power factor measurement.

Last Answer : In an energy meter braking torque is produced to maintain steady speed and equal to driving torque

Last Answer : The damping torque must operate only when the moving system of the indicating instrument is: Actually moving

Description : A moving coil of meter has 100 turns, and a length and depth of 10mm and 20mm respectively. It is positioned in a uniform radial flux density of 200 mT. The coil carrier current capacity is 50 mA. The torque on the coil is

Last Answer : A moving coil of meter has 100 turns, and a length and depth of 10mm and 20mm respectively. It is positioned in a uniform radial flux density of 200 mT. The coil carrier current capacity is 50 mA. The torque on the coil is 200µNm

Last Answer : A moving coil instrument is used as an ohmmeter. The indicating scale of the meter will be Hyperbolic.

Last Answer : In a dynamo-meter type of moving coil instrument a swamping resistance is provided inorder to: Provide equal time constant for moving coil and fixed coil, when used for ac measurement

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

Last Answer : A moving-coil permanent-magnet instrument can be used as flux-meter by eliminating the control springs.

Description : Which of the following instruments have least torque/weight ratio: a) Dynamometer type b) PMMC c) Attraction type moving iron d) Repulsion type moving iron

Last Answer : Ans: A

Description : Horizontally mounted moving iron instruments use   (a) Eddy current damping (b) Electromagnetic damping (c) Fluid friction damping (d) Air friction damping

Last Answer : Horizontally mounted moving iron instruments use Air friction damping

Description : An unshielded moving iron voltmeter is used to measure the voltage in an AC circuit. The stray DC magnetic field having a component along the axis will be  (1) unaffected (2) decreased (3) increased (4) either decreased or increased depending on the direction of the DC field

Last Answer : An unshielded moving iron voltmeter is used to measure the voltage in an AC circuit. The stray DC magnetic field having a component along the axis will be either decreased or increased depending on the direction of the DC field

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

Last Answer : A moving iron ammeter may be compensated for frequency errors by shunt capacitance.

Last Answer : Moving iron and PMMC instruments can be distinguished from each other by looking at: Scale

Last Answer : The moving iron voltmeters are likely: To indicate lower value of ac than on dc.

Description : A 150 V moving iron voltmeter of accuracy class 1.0 reads 75 V when used in a circuit under a standard conditions. The maximum possible percentage error in the reading is:

Last Answer : A 150 V moving iron voltmeter of accuracy class 1.0 reads 75 V when used in a circuit under a standard conditions. The maximum possible percentage error in the reading is:  2.0.

Last Answer : A moving iron instrument can be used for both D.C. and A.C.

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Last Answer : C. Photosensitive

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Last Answer : Answer: Option C

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Last Answer : The effect of stray magnetic fields on the actuating torque of a portable instrument is maximum when the operating field of the instrument and the stray fields are Parallel 

Description : Ideally, the damping torque should be  (1) Proportional to velocity of the moving system and operating current.  (2) Proportional to the velocity of the moving system but independent of operating ... operating current.  (4) Independent of the velocity of the moving system and operating current.

Last Answer : Ideally, the damping torque should be Proportional to the velocity of the moving system but independent of operating current. 

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Last Answer : Answer: A

Description : In a shaft shear stress intensity at a point is not (A) Directly proportional to the distance from the axis (B) Inversely proportional to the distance from the axis (C) Inversely proportional to the polar moment of inertia (D) Directly proportional to the applied torque

Last Answer : (B) Inversely proportional to the distance from the axis

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Last Answer : (D) DC series motor

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Last Answer : The torque, in a DC series motor is proportional to the square of the armature current. 

Last Answer : The armature torque of the D.C. shunt motor is proportional to armature current.

Last Answer :  In a gravity controlled instrument, the deflection angle is proportional to sine inverse of measurand.

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

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Last Answer : Ans. c

Description : In a flux meter, the controlling torque is _____.

Last Answer : In a flux meter, the controlling torque is not provided at all.

Description : For controlling the vibration of the disc of ac energy meter, damping torque is produced by

Last Answer : For controlling the vibration of the disc of ac energy meter, damping torque is produced by Eddy current

Description :  Damping torque used in energy meter is : - a) Electrostatic b) Electro magnetic c) Eddy Current d) None

Last Answer : Damping torque used in energy meter is : - Eddy Current

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Last Answer : A reading of 120 is obtained when a standard inductor was connected in the circuit of a Q-meter and the variable capacitor is adjusted to a value of 300 pF. A lossless capacitor of unknown value Cx is ... when the variable capacitor is readjusted to a value of 200 pF. The value of Cx in pF is 100 

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 : 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 : 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 : 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 : The principle of operation of Q-meter is based on Series resonance.

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Last Answer : For high accuracy the meter has Hand drawn scale.

Description : It is desired to convert a 0-1000A meter movement, with an internal resistance of 100 ohms, into a 0-100mA meter. The required value of shunt resistance is about 

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