61.
The electrical power to a meggar is provided by
A
battery
B
permanent magnet D.C. generator
C
AC.generator
D
any of the above
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The electrical power to a meggar is provided by
battery
permanent magnet D.C. generator
AC.generator
any of the above
The disc of an instrument using eddy current damping should be of
conducting and magnetic material
non-conducting and magnetic material
conducting and non-magnetic material
none of the above
The desirable static characteristics of a measuring system are
accuracy and reproducibility
accuracy, sensitivity and reproducibility
drift and dead zone
static error
The chemical effect of current is used in
D.C. ammeter hour meter
D.C. ammeter
D.C. energy meter
none of the above
The adjustment of position of shading bands, in an energy meter is done to provide
friction compensation
creep compensation
braking torque
none of the above
Systematic errors are
instrumental errors
environmental errors
observational errors
all of the above
Standard resistor is made from
platinum
maganin
silver
nichrome
Resistances can be measured with the help of
wattmeters
voltmeters
ammeters
ohmmeters and resistance bridges
Operating torques in analogue instruments are
deflecting and control
deflecting and damping
deflecting, control and damping
vibration and balancing
Murray loop test can be used for location of
ground fault on a cable
short circuit fault on a cable
both the ground fault and the short-circuit fault
none of the above
Most sensitive galvanometer is
elastic galvanometer
vibration galvanometer
Duddlb galvanometer
spot ballistic galvanometer
Most common form of A.C. meters met with in every day domestic and industrial installations are
mercury motor meters
commutator motor meters
induction type single phase energy meters
all of the above
It is required to measure the true open circuit e.m.f. of a battery. The best device is
D.C. voltmeter
Ammeter and a known resistance
D.C. potentiometer
None of the above
is an instrument which measures the insulation resistance of an electric circuit relative to earth and one another
Tangent galvanometer
Meggar
Current transformer
None of the above
Instrument transformers are
potential transformers
current transformers
both a and b
power transformers
Induction type single phase energy meters measure electric energy in
kW
Wh
kWh
VAR
In Weston synchronoscope the moving coil is connected across
bus-bars
incoming alternator
fixed coils
any of the above
In order to achieve high accuracy, the slide wire of a potentiometer should be
as long as possible
as short as possible
neither too small not too large
very thick
In majority of instruments damping is provided by
fluid friction
spring
eddy currents
all of the above
In an energymeter braking torque is produced to
safe guard it against creep
brake the instrument
bring energy meter to stand still
maintain steady speed and equal to driving torque