A 110V voltmeter can measure a voltage of upto 110kV using a ___
1.110000/110V P.T.
2. 110000V P.T.
3.110V P.T.
4.110/110000V P.T.
C.T. and P.T. are used for ____
1.measuring low current and voltages
2.measuring very low current and voltages
3.measuring high currentsand voltages
4.measuring intermediate currents and voltages
Coils of a C.T. are separately wound.
1. True
2.False
3.all of the above
4.None of the mentioned
How are instrument transformers different from shunts and multipliers?
1. they are all the same
2.they have transformers
3.readings are independent of component values
4. they can be used for high voltages and currents
How can the meter circuit be isolated from the power circuit?
1. by grounding
2.through electrical isolation
3. by physical separation
4.through mechanical isolation
In a 1000/5 A C.T., the number of secondary turns would be ________
1.200
2.199 or 198
3.5
4.1000
In a shell type of core, the windings are ________
1. in the form of the shell
2.shorted with the primary windings
3.not wound
4.placed on the central limb
In the ring type of core, the secondary winding is ________
1.non-uniformly distributed over the core
2. shorted with the primary winding
3. uniformly distributed over the core
4.connected in the form of a ring
Instrument transformers can be easily replaced.
1. True
2. False
3.all of the above
4.None of the mentioned
What is the potential transformer?
1.transformer used with an D.C. ammeter
2. transformer used with an A.C. voltmeter
3. transformer used with an D.C. ammeter
4.transformer used with an A.C. voltmeter
A 5A ammeter can measure a current of upto 1000 A using a ______
1.5/1000A C.T.
2.1000A C.T.
3.5A C.T.
4.1000/5A C.T.
A multiplier is ______
1.non-inductive
2.resistive
3.capacitive
4.non-capacitive
A shunt can be used to measure large currents.
1.True
2.False
3.all of the above
4.None of the mentioned
A shunt is a ______
1.very high resistance
2. medium resistance
3. very low resistance
4. high resistance
At high voltages, the current transformers are enclosed in a tank.
1.True
2.False
3.all of the above
4.None of the mentioned
C.T. and P.T. are standardized at ____
1. 50 A and 220 V
2.25 mA and 2.2 kV
3.5 A and 110 V
4.75 nA and 1.1 MV
Current terminals have a small current capacity.
1.True
2.False
3.all of the above
4.None of the mentioned
Errors are introduced in Current Transformers.
1.True
2.False
3.all of the above
4.None of the mentioned
Errors in a C.T. can be minimised by _____
1.making use of laminations
2.having low reactance
3. increasing the secondary winding turns
4.decreasing the primary winding turns
For a C.T. the turns ratio is defined as the ______
1.n = Np â„ Ns
2.n = 1 â„ Np
3. n = Ns
4.n = Ns â„ Np
For a P.T. the turns ratio is defined as the ______
1.n = Np â„ Ns
2.n = 1 â„ Np
3.n = Ns
4.n = Ns â„ Np
In a C.T., the primary ampere turns is variable.
1.True
2.False
3.all of the above
4.None of the mentioned
In case of AC ammeters, shunts consist of _______
1. impedance
2.capacitance
3. resistance
4. inductance
In power measurements 180° phase shift is required.
1. True
2.False
3.all of the above
4.None of the mentioned
Instrument transformers give same readings irrespective of number of other instruments connected.
1. True
2.False
3.all of the above
4.None of the mentioned
Instrument transformers provide _____
1.electrical isolation from low rated winding
2.electrical isolation from high rated winding
3.electrical isolation from medium rated winding
4.no electrical isolation at all
Moving coil instruments have a current and voltage rating of _______
1.100 A and 25 V
2.50 mA and 50 mV
3.75 nA and 100 μV
4. 25 μA and 75 V
Mumetal has _______
1. low permeability, high loss
2.high permeability, medium loss
3.medium permeability, high loss
4.high permeability, low loss
Nominal ratio of an instrument transformer is defined as the _______
1.reciprocal of the rated primary value
2.ratio of rated secondary value to primary value
3.reciprocal of the rated secondary value
4.ratio of rated primary value to secondary value
Perminder has ______
1.medium saturation point of permeability
2.low saturation point of permeability
3.no saturation point of permeability
4.high saturation point of permeability
Phase angle error is due to _____
1.C.T.
2.magnetising component
3.iron loss
4. supply voltage
Potential terminals have a ______
1.high current capacity
2.low voltage capacity
3. low current capacity
4.high voltage capacity
Range of an electrical instrument depends on ______
1.current
2.voltage
3.power
4. resistance
Ratio correction factor is defined as ____
1.reciprocal of nominal ratio
2.ratio of nominal ratio to transformation ratio
3.ratio of transformation ratio to nominal ratio
4.reciprocal of transformation ratio
Ratio error is defined as ______
1.Ratio error = Knâ„R
2. Ratio error = Kn – Râ„R
3. Ratio error = Kn – R
4.Ratio error = 1â„R
Ratio error is due to ____
1.iron loss
2. C.T.
3.magnetising component
4.supply voltage
Secondary and primary windings consist of ______
1.copper turns
2.14 S.W.G copper wire and copper strip respectively
3. iron coils wound around
4.laminations
The primary winding of a C.T. has ____
1.a larger number of turns
2.no turns at all
3. intermediate number of turns
4.a few turns
The primary winding of a P.T. has _____
1. intermediate number of turns
2.no turns at all
3.a larger number of turns
4.a few turns
The secondary leakage reactance of a C.T. ______
1. increases its ratio error
2.decreases its ratio error
3.has no effect on its ratio error
4.increases the impedance of the circuit
The secondary winding of a C.T. has ______
1.a large number of turns
2.a few turns
3. no turns at all
4.intermediate number of turns
The secondary winding of a P.T. has _______
1. a large number of turns
2. intermediate number of turns
3. no turns at all
4.a few turns
The windings of a C.T. are _______
1.tied together
2.shorted
3.wound over one another
4.grounded
Transformation ratio of an instrument is defined as _______
1. ratio of primary to secondary phasor
2.ratio of secondary to primary phasor
3.reciprocal of the primary phasor
4.reciprocal of the secondary phasor
Turns compensation is used to obtain ____
1.to compensate the turns
2. to equalise the turns on the windings
3. to protect the equipment
4.transformation ratio equal to nominal ratio
Turns ration for a C.T. is _______
1.n = Np â„ Ns
2.n = Ns â„ Np
3.n = 1 â„ Np
4.n = Ns
What is the condition for using a multiplier in A.C. voltmeters?
1. by using ac supply
2.by maintaining a uniform impedance
3.by maintaining a uniform frequency
4.by using a galvanometer
What is the current transformer?
1. transformer used with an A.C. ammeter
2.transformer used with an D.C. ammeter
3.transformer used with an A.C. voltmeter
4.transformer used with an D.C. voltmeter
What is the effect of reducing the secondary turns in a C.T. by 1%?
1. transformation ratio reduces by the same value
2.no effect
3.nominal ratio increase by the same value
4.secondary current increases by the same value
What is the effect of the ammeter range on the shunt resistance?
1.no effect
2.varies by a factor of multiplying factor
3.varies by a factor of the resistance
4.varies by a factor of unity