# There will be serious errors, if Power factor of non-sinusoidal Waveforms is measured by electrodynamometer power factor meters. This is true of

1.  only single phase meters

2.  only 3 phase meters

3.  both single and three phase meters

4.  none of these

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only single phase meters

Explanation :
No Explanation available for this question

# A resistance Of value 10 c2 approximately is to be measured voltmeter method with resistance of ammeter is 0.02Ω and that of voltmeter is 5000Ω The resistance should be Measured by

1.  connecting the ammeter on the side of unknown resistance as this connection

2.  connection the voltmeter on the side of unknown resistance as this connection gives batter accuracy

3.  any of the two connection, as both of them give equal accuracy

4.  none of these

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connecting the ammeter on the side of unknown resistance as this connection

Explanation :
No Explanation available for this question

# The power consumption of a d.c. voltmeter using a direct coupled amplifier when measuring a voltage 0.5 V is of the order of a few

1.  watt

2.  milliwatt

3.  microwatt

4.  nanowatt

4

nanowatt

Explanation :
No Explanation available for this question

# A true rms reading voltmeter uses two thermocouples in order

1.  to increase sensitivity

2.  that the second thermocouple cancels out the no-linear effects of the first thermocouple

3.  to prevent drift in the d.c. amplifier

4.  all of these

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that the second thermocouple cancels out the no-linear effects of the first thermocouple

Explanation :
No Explanation available for this question

# A current transformer has a rating of 100/5 A. Its magnetizing and loss component of exciting current are 10 A and 0.6 A respectively and secondary winding burden is purely resistive, its transformation ratio at rated current is

1.  20.12

2.  20.2

3.  200.2

4.  none of these

4

20.12

Explanation :
No Explanation available for this question

# A current transformer has a rating of 1000/5 A. Its magnetizing current and loss component of exciting current are 10 A and 6 A respectively. The phase angle between secondary winding induced voltage and current is 300. The phase angle error of the transformer at rated current is

1.  0.650

2.  0.3050

3.  0.4960

4.  none of these

4

none of these

Explanation :
No Explanation available for this question

# The errors in current transformers can be reduced by designing them with

1.  high permeability and low loss core materials, avoiding any joints. in the core and also keeping the flux density to a low value

2.  using primary and secondary windings as close to each other as possible

3.  using large cross-sections for both primary and secondary winding conductors

4.  all of these

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high permeability and low loss core materials, avoiding any joints. in the core and also keeping the flux density to a low value

Explanation :
No Explanation available for this question

# Turns compensation is used in current transformers primarily for reduction of

1.  phase angle error

2.  both ratio and phase angle errors

3.  ratio error reduction in phase error is incidental

4.  none of these

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ratio error reduction in phase error is incidental

Explanation :
No Explanation available for this question

# The ratio and phase angle errors in potential transformers may be reduced by

1.  increasing the exciting current

2.  increasing the resistance and leakage reactance in the transformer

3.  by not employing turns compensation

4.  none of these

4

none of these

Explanation :
No Explanation available for this question

# Capacitive potential transformers are used

1.  for primary winding phase voltages above 100 kV

2.  for keeping the value of transformation ratio constant irrespective of the burden by making certain adjustment

3.  because they are cheaper than the electromagnetic trans-formers above a certain voltage range

4.  all of these

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