Why not high resistance for earth fault than using grounding transformer & resistor 0.45 ohms?

Why not high resistance for earth fault than using grounding transformer & resistor 0.45 ohms?
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It is mechanically unwide. Difficult to manufacture.  
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A transformer has a turns ratio of two to one. If a 100 ohm resistor is connected on the high side, its resistance as measured on the low side would be: w) 25 ohms x) 50 ohms y) 100 ohms z) 400 ohms

Description : A transformer has a turns ratio of two to one. If a 100 ohm resistor is connected on the high side, its resistance as measured on the low side would be: w) 25 ohms x) 50 ohms y) 100 ohms z) 400 ohms

Last Answer : ANSWER: W -- 25 OHMS

When earth fault occurs: a) voltage potential at the earth mat increases due to grounding b) voltage potential at the earth mat decreases due to grounding c) voltage potential at the earth mat remains zero irrespective of fault d) none of the above

Description : When earth fault occurs: a) voltage potential at the earth mat increases due to grounding b) voltage potential at the earth mat decreases due to grounding c) voltage potential at the earth mat remains zero irrespective of fault d) none of the above

Last Answer : Ans: A

What power would be consumed by the series resistor of the circuit shown in the illustration if the source is 30 volts, the resistance of R1 is 10 ohms, R2 is 10 ohms, and R3 is 10 ohms? EL-0032 A. 5 watts B. 10 watts C. 20 watts D. 40 watts

Description : What power would be consumed by the series resistor of the circuit shown in the illustration if the source is 30 volts, the resistance of R1 is 10 ohms, R2 is 10 ohms, and R3 is 10 ohms? EL-0032 A. 5 watts B. 10 watts C. 20 watts D. 40 watts

Last Answer : Answer: D

What would be the voltage drop across the series resistor of the circuit shown in the illustration if the source is 30 volts, the resistance of R1 is 10 ohms, R2 is 10 ohms and R3 is 10 ohms? EL-0032 A. 5 volts B. 10 volts C. 20 volts D. 30 volts

Description : What would be the voltage drop across the series resistor of the circuit shown in the illustration if the source is 30 volts, the resistance of R1 is 10 ohms, R2 is 10 ohms and R3 is 10 ohms? EL-0032 A. 5 volts B. 10 volts C. 20 volts D. 30 volts

Last Answer : Answer: C

When a voltage of 115 VDC is applied to the illustrated circuit with a resistance of 10,230 ohms the current will be _______ EL-0018 A. 88.95 milliamps B. 103.45 milliamps C. 11.24 milliamps D. 0.91 amps

Description : When a voltage of 115 VDC is applied to the illustrated circuit with a resistance of 10,230 ohms the current will be _______ EL-0018 A. 88.95 milliamps B. 103.45 milliamps C. 11.24 milliamps D. 0.91 amps

Last Answer : Answer: C

A 1:5 step-up transformer has 120V across the primary and 600 ohms resistance across the secondary. Assuming 100% efficiency, the primary current equals (A) 0.2 Amp. (B) 5 Amps. (C) 10 Amps. (D) 20 Amps.

Description : A 1:5 step-up transformer has 120V across the primary and 600 ohms resistance across the secondary. Assuming 100% efficiency, the primary current equals (A) 0.2 Amp. (B) 5 Amps. (C) 10 Amps. (D) 20 Amps.

Last Answer : I1= V1 /R1 = 120/600 = 0.2 (η = 100%, losses are zero ∴V1 = VR = I1R1)

What is the resistance value indicated by the multimeter scale illustrated, if the range switch is set at R X 1, and the needle is at the position indicated by the letter 'B'? EL-0047 A. 1.45 ohms B. 7.2 ohms C. 37 ohms D. 70 ohms

Description : What is the resistance value indicated by the multimeter scale illustrated, if the range switch is set at R X 1, and the needle is at the position indicated by the letter 'B'? EL-0047 A. 1.45 ohms B. 7.2 ohms C. 37 ohms D. 70 ohms

Last Answer : Answer: D

What would be the total power consumed in the circuit shown in the illustration if the source is 30 volts the resistance for R1 is 10 ohms, R2 is 10 ohms, and R3 is 10 ohms? EL-0032 A. 10 watts B. 40 watts C. 45 watts D. 60 watts

Description : What would be the total power consumed in the circuit shown in the illustration if the source is 30 volts the resistance for R1 is 10 ohms, R2 is 10 ohms, and R3 is 10 ohms? EL-0032 A. 10 watts B. 40 watts C. 45 watts D. 60 watts

Last Answer : Answer: D

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Description : Which of the listed electrical devices is represented by the symbol shown in the illustration? EL-0055 A. Fixed resistance resistor B. Coil with magnetic core C. DC motor or generator shunt field D. Transformer

Last Answer : Answer: D

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Description : Why 6.6 kV transformer is resistance grounded by 10 ohms and current limited to 400 A?

Last Answer : a) To reduce burning and melting in faulted switchgear or machine. b) To reduce mechanical stresses in equipment. c) To reduce the electrical hazards by stray ground fault currents in the ground ... screen in 6.6 kV XLPE (cross-linked polyethylene). Therefore the cost of the cable decreases. 

WHAT is ZIG ZAG Grounding Transformer

Description : WHAT is ZIG ZAG Grounding Transformer

Last Answer : ANSWER: Three Single Phase Transformers can be connected to have a three phase Zig Zag Transformer. This system can be used for either grounding or developing a fourth WIRE from a three phase neutral. An example ... - three phase - three wire system to a 480Y/277 V - three phase - four wire system

What is the purpose of grounding secondary of the control transformer?

Description : What is the purpose of grounding secondary of the control transformer? 

Last Answer : To protect the operating personnel from high induced voltage.  

Ground resistance should be designed such that: a) grounding resistance should be as low as possible b) grounding resistance should be as high as possible c) grounding resistance should be always zero d) none of the above

Description : Ground resistance should be designed such that: a) grounding resistance should be as low as possible b) grounding resistance should be as high as possible c) grounding resistance should be always zero d) none of the above

Last Answer : Ans: A

A carbon resistor has a resistance of 50 ohms, and a tolerance of 5 percent. What are the colors of bands one, two, three, and four, respectively?

Description : A carbon resistor has a resistance of 50 ohms, and a tolerance of 5 percent. What are the colors of bands one, two, three, and four, respectively?

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Four equal resistors are connected in parallel, each resistor has an ohmic value of 100 ohms, what is the equivalent resistance?

Description : Four equal resistors are connected in parallel, each resistor has an ohmic value of 100 ohms, what is the equivalent resistance?

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A circuit is to be designed in which a capacitor must charge to 40 percent of the maximum charging voltage in 200 microseconds. The resistor to be used has a resistance of 40,000 ohms. What size capacitor must be used?

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When 2,4 and 6 ohms resistor are connected in parallel their resultant equivalent resistance will be A. 12ohm b. 11/12ohm C. 12/11ohm d. None

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A circuit has a resistance of 200 ohms. The resistance of the circuit can be reduced to 120 ohms by adding which of the following to the circuit. w) 80 ohm resistor in series x) 150 ohm resistor in parallel y) 240 ohm resistor in series z) 300 ohm resistor in parallel

Description : A circuit has a resistance of 200 ohms. The resistance of the circuit can be reduced to 120 ohms by adding which of the following to the circuit. w) 80 ohm resistor in series x) 150 ohm resistor in parallel y) 240 ohm resistor in series z) 300 ohm resistor in parallel

Last Answer : ANSWER: Z -- 300 OHM RESISTOR IN PARALLEL

A resistor with the color coded value of 1000 ohms and ± 10% tolerance can have an actual resistance...

Description : A resistor with the color coded value of 1000 ohms and ± 10% tolerance can have an actual resistance between ________. A. 990 ohm and 1010 ohm B. 900 ohm and 1100 ohm C. 1000 ohm and 1100 ohm D. 900 ohm and 1000 ohm. 

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Description : Why resistance grounding preferred for less than 33 kV and more than 415 V?

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45 The function of conservator in a transformer is A. To protect against internal fault B. To reduce copper as well as core losses C. To cool the transformer oil D. To take care of the expansion and contraction of transformer oil due to variation of temperature of surroundings

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What is different between resistance grounding system and resistance earthing system?

Description : What is different between resistance grounding system and resistance earthing system?

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How value of grounding resistance could be kept constant?

Description : How value of grounding resistance could be kept constant?

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How grounding resistance could be measured?

Description : How grounding resistance could be measured?

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What does mean by grounding electrode, grounding system, and grounding resistance?

Description : What does mean by grounding electrode, grounding system, and grounding resistance? 

Last Answer : Grounding electrode: A conductor driven in the earth and used for collecting ground current from or dissipating ground current into the earth.  Grounding system: Comprises all interconnected ... current is discharged to the ground through a particular grounding electrode or grounding system. 

The lowest resistance grounding on earth A. Sand B. Clay C. Surface loam soil D. Limestone

Description : The lowest resistance grounding on earth A. Sand B. Clay C. Surface loam soil D. Limestone

Last Answer : C. Surface loam soil

When using a multimeter for resistance measurements, it should be calibrated by clipping the loose ends of the leads together and _____________. A. setting the instrument pointer at 'zero' ohms B. adjusting the line voltage to calibrate the instrument C. plugging each end of one test lead into the plus and minus terminals D. using a special purpose resistance measuring instrument (a bridge)

Description : When using a multimeter for resistance measurements, it should be calibrated by clipping the loose ends of the leads together and _____________. A. setting the instrument pointer at 'zero' ohms B. ... the plus and minus terminals D. using a special purpose resistance measuring instrument (a bridge)

Last Answer : Answer: A

You are calibrating a multimeter using internal batteries to supply power for resistance measurements. However, you are unable to adjust the pointer to 'zero' using the adjustment knob. Therefore, you should _____________. A. replace the batteries in the instrument B. measure resistance by dividing the voltmeter indication by the ammeter indication C. set the pointer using a bridge D. change scales to the R X 100 scale and adjust using the 'zero ohms' adjusting knob

Description : You are calibrating a multimeter using internal batteries to supply power for resistance measurements. However, you are unable to adjust the pointer to 'zero' using the adjustment knob. Therefore, you should ... change scales to the R X 100 scale and adjust using the 'zero ohms' adjusting knob

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Why in transformer the LV CB also be tripped along with HV CB for a primary side fault?

Description : Why in transformer the LV CB also be tripped along with HV CB for a primary side fault?

Last Answer : Auxiliary transformer 415v delta star transformer, if HV CB alone tripped then back feeding from LV side (say DG runs parallel with transformer)—arcing voltage at the fault on primary—fault fed for more time – more damage.  

Purpose of Over current & earth fault relay; type- CAG

Description : Purpose of Over current & earth fault relay; type- CAG  

Last Answer : This relays are designed for instantaneous phase or earth fault protection and instantaneous high set over current protection.; A standard hinged-armature unit forms the basic movement for this relay. It consists an ... to the end of the core while the other arm to operate a set of contacts.  

Purpose of Directional inverse Over current & earth fault relay; type- CDD

Description : Purpose of Directional inverse Over current & earth fault relay; type- CDD

Last Answer : Directional phase or earth fault protection of ring-mains, parallel transformers, transformer feeders, parallel feeders etc., employing the time graded principle.; This relay comprises an inductive ... induction disc unit. The directional unit is normally provided with voltage polarising coils. 

An ammeter has a full-scale deflection current of 100mA. If the same ammeter is used to measure a full-scale current of 1.0ampere, what is the value of the shunt resistor in ohms if the voltage across the meter is 9.0 volts?

Description : An ammeter has a full-scale deflection current of 100mA. If the same ammeter is used to measure a full-scale current of 1.0ampere, what is the value of the shunt resistor in ohms if the voltage across the meter is 9.0 volts?

Last Answer : 10 ohms

The insulation of electric generators during short idle periods should be _____________. A. allowed to cool slowly to ambient temperatures B. flashed with direct current to remove any residual magnetism C. kept warm by using strip or space heaters D. relieved of all capacitive charge by grounding the conductors

Description : The insulation of electric generators during short idle periods should be _____________. A. allowed to cool slowly to ambient temperatures B. flashed with direct current to remove any residual ... using strip or space heaters D. relieved of all capacitive charge by grounding the conductors

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A load with an impedance of 440 ohms is connected across the secondary of the transformer illustrated. If the input voltage is 110 VAC and the step-up ratio is 10 to 1, what will be the primary current? EL-0055 A. 2.5 amps B. 25 amps C. 250 amps D. current cannot be determined with information given

Description : A load with an impedance of 440 ohms is connected across the secondary of the transformer illustrated. If the input voltage is 110 VAC and the step-up ratio is 10 to 1, what will be the primary current? EL-0055 A. 2.5 amps B. 25 amps C. 250 amps D. current cannot be determined with information given

Last Answer : Answer: B

Motor controllers are seldom troubled with grounds because _____________. A. the auxiliary contacts have a high resistance connection B. the contactors and relays are mounted on a nonconducting panel C. the resistor banks are composed of individual series-connected units D. there are separate switches for the motor and the control

Description : Motor controllers are seldom troubled with grounds because _____________. A. the auxiliary contacts have a high resistance connection B. the contactors and relays are mounted on a nonconducting panel ... individual series-connected units D. there are separate switches for the motor and the control

Last Answer : Answer: B

A 1:5 step-up transformer has 120V across the primary and 600 ohms resistance across the secondary....

Description : A 1:5 step-up transformer has 120V across the primary and 600 ohms resistance across the secondary. Assuming 100% efficiency, the primary current will be:  (A) 0.2 Amp. (B) 5 Amps. (C)10 Amps. (D) 20 Amps

Last Answer : C. 10A

When a voltage of 132 VDC is applied to the illustrated circuit with a resistance of 237 ohms the current will be ________. EL-0018 A. 1.236 amps B. 2.048 amps C. 0.557 amps D. 4.200 amps

Description : When a voltage of 132 VDC is applied to the illustrated circuit with a resistance of 237 ohms the current will be ________. EL-0018 A. 1.236 amps B. 2.048 amps C. 0.557 amps D. 4.200 amps

Last Answer : Answer: C

When a voltage of 132 VDC is applied to the illustrated circuit with a resistance of 470 ohms the current will be ________. EL-0018 A. 0.280 amps B. 3.560 amps C. 602 milliamps D. 1.673 amps

Description : When a voltage of 132 VDC is applied to the illustrated circuit with a resistance of 470 ohms the current will be ________. EL-0018 A. 0.280 amps B. 3.560 amps C. 602 milliamps D. 1.673 amps

Last Answer : Answer: A

When a voltage of 132 VDC is applied to the illustrated circuit with a resistance of 10,230 ohms the current will be ________. EL-0018 A. 0.012 amps B. 77.5 milliamps C. 10,362 amps D. 0.792 amps

Description : When a voltage of 132 VDC is applied to the illustrated circuit with a resistance of 10,230 ohms the current will be ________. EL-0018 A. 0.012 amps B. 77.5 milliamps C. 10,362 amps D. 0.792 amps

Last Answer : Answer: A

When a voltage of 132 VDC is applied to the illustrated circuit with a resistance of 110 ohms the current will be ________. EL-0018 A. 0.833 amps B. 1.2 amps C. 2.2 amps D. 242 milliamps

Description : When a voltage of 132 VDC is applied to the illustrated circuit with a resistance of 110 ohms the current will be ________. EL-0018 A. 0.833 amps B. 1.2 amps C. 2.2 amps D. 242 milliamps

Last Answer : Answer: B

When a voltage of 132 VDC is applied to the illustrated circuit with a resistance of 32 ohms the current will be ________. EL-0018 A. 0.242 amps B. 4.125 amps C. 7.757 amps D. 1.64 amps

Description : When a voltage of 132 VDC is applied to the illustrated circuit with a resistance of 32 ohms the current will be ________. EL-0018 A. 0.242 amps B. 4.125 amps C. 7.757 amps D. 1.64 amps

Last Answer : Answer: B

If a voltage of 132 VDC is applied to the illustrated circuit where the resistance is 12 ohms, then current will be ___________. EL-0018 A. 0.090 amps B. 1.090 amps C. 11 amps D. 144 milliamps

Description : If a voltage of 132 VDC is applied to the illustrated circuit where the resistance is 12 ohms, then current will be ___________. EL-0018 A. 0.090 amps B. 1.090 amps C. 11 amps D. 144 milliamps

Last Answer : Answer: C

When a voltage of 124 VDC is applied to the illustrated circuit with a resistance of 17.8 ohms the current will be ________. EL-0018 A. 0.143 amps B. 2.555 amps C. 6.966 amps D. 141.8 milliamps

Description : When a voltage of 124 VDC is applied to the illustrated circuit with a resistance of 17.8 ohms the current will be ________. EL-0018 A. 0.143 amps B. 2.555 amps C. 6.966 amps D. 141.8 milliamps

Last Answer : Answer: C

When a voltage of 124 VDC is applied to the illustrated circuit with a resistance of 470 ohms the current will be________. EL-0018 A. 0.263 amps B. 3.79 amps C. 594 milliamps D. 1.7814 amps

Description : When a voltage of 124 VDC is applied to the illustrated circuit with a resistance of 470 ohms the current will be________. EL-0018 A. 0.263 amps B. 3.79 amps C. 594 milliamps D. 1.7814 amps

Last Answer : Answer: A

When a voltage of 124 VDC is applied to the illustrated circuit with a resistance of 10,230 ohms the current will be________. EL-0018 A. 0.012 amps B. 82.50 amps C. 10.354 amps D. 0.8439 amps

Description : When a voltage of 124 VDC is applied to the illustrated circuit with a resistance of 10,230 ohms the current will be________. EL-0018 A. 0.012 amps B. 82.50 amps C. 10.354 amps D. 0.8439 amps

Last Answer : Answer: A

When a voltage of 124 VDC is applied to the illustrated circuit with a resistance of 110 ohms the current will be________. EL-0018 A. 0.887 amps B. 1.127 amps C. 234 m amps D. 2.13 amps

Description : When a voltage of 124 VDC is applied to the illustrated circuit with a resistance of 110 ohms the current will be________. EL-0018 A. 0.887 amps B. 1.127 amps C. 234 m amps D. 2.13 amps

Last Answer : Answer: B

When a voltage of 124 VDC is applied to the illustrated circuit with a resistance of 32 ohms the current will be ________. EL-0018 A. 0.258 amps B. 3.875 amps C. 8.258 amps D. 156 amps

Description : When a voltage of 124 VDC is applied to the illustrated circuit with a resistance of 32 ohms the current will be ________. EL-0018 A. 0.258 amps B. 3.875 amps C. 8.258 amps D. 156 amps

Last Answer : Answer: B

When a voltage of 124 VDC is applied to the illustrated circuit with a resistance of 12 ohms. the current will be ________. EL-0018 A. 0.096 amps B. 1.16 amps C. 10.33 amps D. 136 m amps

Description : When a voltage of 124 VDC is applied to the illustrated circuit with a resistance of 12 ohms. the current will be ________. EL-0018 A. 0.096 amps B. 1.16 amps C. 10.33 amps D. 136 m amps

Last Answer : Answer: C

When a voltage of 110 VDC is applied to the circuit illustrated with a resistance of 10,230 ohms the current will be________. EL-0018 A. 0.0107 amps B. 93 amps C. 10,340 amps D. .951 amps

Description : When a voltage of 110 VDC is applied to the circuit illustrated with a resistance of 10,230 ohms the current will be________. EL-0018 A. 0.0107 amps B. 93 amps C. 10,340 amps D. .951 amps

Last Answer : Answer: A