# In moving coil meters, damping is provided by

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In moving coil meters, damping is provided by eddy current disk.

## Related questions

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

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The power in a 3-phase load is measured by two watt meters. If one watt meter reads zero, then the load power factor is (A) Zero (B) 0.5 (C ) 0.866 (D) unity

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Eddy current damping cannot be used for moving iron instrument because

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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

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Series resistance required to read 0-250 V with a moving coil instrument of internal resistance 2 ohm and full scale deflection of 50 mA is (a) 49998 Ω (b) 4998 Ω (c) 498 Ω (d) 49.8 Ω

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Two voltmeters of same range, one moving iron type and other permanent magnet moving coil type, are connected in parallel for measuring a.c. supply voltage. If the reading of MI type is 300V, the reading of PMMC type will be (a) zero (b) higher-than M.I. type (c) lower than M.I. type (d) same

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A permanent magnet moving coil ammeter has a coil resistance of 99 ohm and Full Scale Deflection (FSD) current of 0.1mA. Shunt resistance is 1 ohm. Current through the meter at 0.5 F.S.D is:

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A moving coil instrument has a resistance of 10 W and gives full scale deflection when carrying a current of 50 mA. To measure current upto 100 A, we will have to connect • 10 W resistance in series • 10 W resistance in parallel • 10/1999 W resistance in series • 10/1999 W resistance in parallel

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Permanent magnet moving coil instruments are used for

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In moving iron instruments, eddy current damping cannot be used as  (a) They have a strong operating magnetic, field (b) They are not normally used in vertical position (c) They need a large damping force, which can only be provided by air friction (d) The introduction of a permanent magnet required for eddy current damping would distort the existing weak operating magnetic field

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

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Moving coil in dynamometer wattmeter connected : - a) in series with fixed coil b) across supply c) in series with load d) across load

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The main sources of Errors in Permanent Magnet moving Coil (PMMC) are due to : - a) weaking of the permanent magnet due to aging at temperature effects b) weaking of spring due to aging and temperature effects c) change of resistance of the moving coil with temperature d) all the above

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Eddy current damping is normally used in the instruments of (a) Induction type (b) Moving iron type (c) Permanent magnet moving coil type (d) Nothing can be said

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In the time response analysis of control system, Damping Ratio is given by - a) Actual damping / Critical damping b) Critical damping /Actual damping c) ( Sum of the Actual damping and critical damping) /Actual damping d)( Difference of the Actual damping and critical damping) / critical damping

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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

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In BJT circuits, bulk of the gain is provided by (A) CE configuration (B) CB configuration (C) CC configuration (D) It is not certain

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For internal faults in generator, the primary protection is provided by (1) Earth fault relay (2) Differential relay (3) Induction type inverse definite minimum time relay (4) Definite minimum time relay

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In a portable instrument, the controlling torque is provided by  A) Spring B) gravity C) eddy currents D) all of the above

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In dynamometer type of wattmeter, which of the coil is split up into two parts?

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State the material used for moving coil and former for PMMC instruments.

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Moving coil instruments have which one of the following scales ? (a) Logarithmic scale (b) Uniform scale (c) Non-uniform scale (d) Squared scale

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A moving coil meter has a resistance of 3 Ω and gives full scale deflection with 30 mA. To measure voltage up to 300 V, the external resistance to be connected in series with the instrument is (A) 9997 Ω (B) 10000 Ω (C) 997 Ω (D) 10003 Ω

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A moving coil instrument of resistance 5 Ohm requires a potential difference of 75 mV to give a full scale deflection. The value of shunt resistance needed to give a full scale deflection at 30 A is

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The deflecting torque of a moving coil instrument depends on (a) supply frequency (c) flux in the coil (b) inverse of area of coil (d) square of the voltage

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A moving coli ammeter has a fixed shunt of 0.02 Ω with a coil circuit resistance of R=1 kΩ and needs potential of 0.5 V across it for full scale deflection. Calculate the value of shunt to give full scale deflection when the total current is 10 A. (1) 0.05 Ω (2) 0.005 Ω (3) 0.5 Ω (4) 0.0005 Ω