What is meant by tan-delta measurement?

What is meant by tan-delta measurement?
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1 Answer

Answer :

It is the tan of the angle between the capacitive current and the total current.

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As the value of tan delta increases the resistive component of the current in increasing. Hence it shows a weak insulation.  

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Related questions

What is the purpose of tan-delta measurement?

Description : What is the purpose of tan-delta measurement? 

Last Answer : Insulation in electrical system has parameters such as Capacitance, Die-electric loss, and Power factor. By detecting the changes in these parameters failures can be revealed. In this tan-delta ... insulation. This detects moisture and void in the insulation. This indicates amount of ionization. 

What do you understand by tan delta for a insulating material?

Description : What do you understand by tan delta for a insulating material?

Last Answer : Tan delta measurement is done to find the qualities of insulating material. Tan delta is angle between current due to surface leakage or current due to capacitance and the capacitive current. That is Tan δ = Ir / Ic. 

In the illustration, the tan and white wires are connected to the solenoid valve. The solinoid valve is_________. EL-0043 A. in the liquid line before the TXV B. energized and open whenever the unit is plugged in C. not grounded so the unit must be modified before using aboard ship D. the water inlet for the ice maker

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Last Answer : Answer: D

In the illustration, the tan and white wires are connected to the solenoid valve. The solenoid valve is_________. EL-0042 A. in the liquid line before the TXV B. energized and open whenever the unit is plugged in C. not grounded so the unit must be modified before using aboard ship D. the water inlet for the ice maker

Description : In the illustration, the tan and white wires are connected to the solenoid valve. The solenoid valve is_________. EL-0042 A. in the liquid line before the TXV B. energized and open whenever the unit ... so the unit must be modified before using aboard ship D. the water inlet for the ice maker

Last Answer : Answer: D

If P is the power of a star connected system then what will be power of an equivalent delta connected system? A..P B. 3P C. P/3 D. None of the above

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The electrical schematic illustrated in figure A, depicts a/an _____________. EL-0059 A. autotransformer B. Delta Wye transformer C. primary EMF generator D. potential transformer

Description : The electrical schematic illustrated in figure A, depicts a/an _____________. EL-0059 A. autotransformer B. Delta Wye transformer C. primary EMF generator D. potential transformer

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In a three-phase, open-delta connected transformer, the line current is equal to _____________. A. the phase current B. three times the phase current C. the sum of any two phase currents D. the difference of any two phase currents

Description : In a three-phase, open-delta connected transformer, the line current is equal to _____________. A. the phase current B. three times the phase current C. the sum of any two phase currents D. the difference of any two phase currents

Last Answer : Answer: A

One important difference between wye-connected and delta-connected generators is that delta connections have ____________. A. line voltages equal to the vector sum of the phase voltages B. phase voltages 90° out of sync C. line current equal to the phase current D. line voltage equal to the phase voltage

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Current measuring instruments must always be connected in _____________. A. series with a circuit B. parallel with a circuit C. series-parallel with a circuit D. delta with the shunt

Description : Current measuring instruments must always be connected in _____________. A. series with a circuit B. parallel with a circuit C. series-parallel with a circuit D. delta with the shunt

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Which of the following procedures should be used to determine the load of a threephase, delta wound, AC generator? A. Multiply the amperage in one phase by three. B. Divide the total amperage in all phases by three. C. Multiply the amperage in one phase by the square root of three. D. Divide the total amperage in all phases by the square root of three.

Description : Which of the following procedures should be used to determine the load of a threephase, delta wound, AC generator? A. Multiply the amperage in one phase by three. B. Divide the total amperage in all ... square root of three. D. Divide the total amperage in all phases by the square root of three.

Last Answer : Answer: C

In testing a three-phase delta winding for an open circuit using a megohmmeter, you must ______________. A. test each phase with all connections intact B. measure the voltage across the open connections while testing C. test the windings as parallel groups to avoid short circuiting D. open the delta-connections to avoid shunting the phase being tested

Description : In testing a three-phase delta winding for an open circuit using a megohmmeter, you must ______________. A. test each phase with all connections intact B. measure the voltage across the open ... groups to avoid short circuiting D. open the delta-connections to avoid shunting the phase being tested

Last Answer : Answer: D

Which of the listed figures shown in the illustration represents devices connected in a three-phase delta-delta arrangement? EL-0084 A. A B. B C. C D. D

Description : Which of the listed figures shown in the illustration represents devices connected in a three-phase delta-delta arrangement? EL-0084 A. A B. B C. C D. D

Last Answer : Answer: A

Which of the listed figures shown in the illustration represents devices connected in a three-phase delta-wye arrangement? EL-0084 A. A B. B C. C D. D

Description : Which of the listed figures shown in the illustration represents devices connected in a three-phase delta-wye arrangement? EL-0084 A. A B. B C. C D. D

Last Answer : Answer: C

Which of the listed figures shown in the illustration represents devices connected in a three-phase wye-delta arrangement? EL-0084 A. A B. B C. C D. D

Description : Which of the listed figures shown in the illustration represents devices connected in a three-phase wye-delta arrangement? EL-0084 A. A B. B C. C D. D

Last Answer : Answer: D

Disadvantages of Star-Delta Starting of Induction motor?

Description : Disadvantages of Star-Delta Starting of Induction motor?

Last Answer : In Star-Delta starting induction motor stator is connected in star connection for starting after picking up speed it is connected to delta connection. When induction motor is connected in star connection ... . This also results in reduced starting torque (1/3 times compared to delta connection).

What advantage has the star connection over the delta connection ?

Description : What advantage has the star connection over the delta connection ?

Last Answer : A. Each star connection transformer is wound for only 57.7% of line voltage . In hv transmission, this admits of much smaller transformer being built for high voltage than possible with delta connection, because of less insulation.

What is the advantage is obtained in the delta connection ?

Description : What is the advantage is obtained in the delta connection ?

Last Answer : A. When three transformer are obtained in delta, one may be removed and two remaining unit will carry 57.7% of the original three phase load and thus maintain the continuity of supply.

Why Delta Star Transformers are used for Lighting Loads?

Description : Why Delta Star Transformers are used for Lighting Loads?

Last Answer : A. For lighting loads, neutral conductor is must and hence the secondary must be star winding.This lighting load is always unbalanced in all three phases. To minimize the current unbalance in the primary we use delta winding in the primary. So delta / star transformer is used for lighting loads.

What is the difference between delta-delta, delta-star transformer?

Description : What is the difference between delta-delta, delta-star transformer?

Last Answer : A. Delta-delta transformer is used at generating station or a receiving station for Change of Voltage (i,e) generally it is used where the Voltage is high & Current is low whereas Delta-star ... star neutral is taken as a return path and this configuration is used for Step down voltage phenomena.

Why Delta Star transformer Are Used For Lighting Loads?

Description : Why Delta Star transformer Are Used For Lighting Loads?

Last Answer : For lighting loads, neutral conductor is must and hence the secondary must be star winding. and this lighting load is always unbalanced in all three phases. To minimize the current unbalance in the primary we use delta winding in the primary. So delta / star trformer is used for lighting loads.

Why input transformer of PUPS module 1 is delta-delta and module 2 is delta-star?

Description : Why input transformer of PUPS module 1 is delta-delta and module 2 is delta-star?

Last Answer : With the help of this arrangement, combined DC output from both chargers is equivalent to that from a 12-pulse rectifier. Advantage of 12-pulse rectifier is that the mains current is fairly close ... phase angle difference 30-degree between module 1 output and module 2 output give 12-pulse output. 

Why delta – delta CT’s are used for star – star transformer differential protection?

Description : Why delta – delta CT’s are used for star – star transformer differential protection?

Last Answer : Say primary neutral is not solidly earthed. Then for any earthfault on secondary terminal, the primary current distribution is so for external fault, the differential is likely to operate if sequence current ... into relay. The 2:1:1 distribution is possibly only for core type or delta tertiary.

State the voltage and current relation in star and delta connection.

Description : State the voltage and current relation in star and delta connection. 

Last Answer : In star connection line current is equal to the phase current and line voltage is √3 times that of phase voltage. In delta connection line voltage is equal to the phase voltage and line current is √3 times that of phase current. 

What is the impedance per phase of delta connected motor?

Description : What is the impedance per phase of delta connected motor?

Last Answer : 1.5 times the total impedance.

What are the value of voltage and current in star connection and in delta connection?

Description : What are the value of voltage and current in star connection and in delta connection?

Last Answer : Star connection a. IL = IPh. b. VL = √3 VPh. ∴ VPh = VL/√3. Note: in star connection we are getting neutral point and we can able to measure the phase as well as line voltage. Delta connection a. VL = VPh. b. IL = √3 IPh. ∴ IPh = IL/√3.

What are the advantages of star-delta starter with induction motor?

Description : What are the advantages of star-delta starter with induction motor?

Last Answer : The main advantage of using the star delta starter is reduction of current during the starting of the motor. Starting current is reduced to 3-4 times of current of Direct online starting Hence the starting current is reduced , the voltage drops during the starting of motor in systems are reduced

Why Delta Star Transformers are used for Lighting Loads?

Description : Why Delta Star Transformers are used for Lighting Loads?

Last Answer : For lighting loads, neutral conductor is must and hence the secondary must be star winding and this lighting load is always unbalanced in all three phases.  To minimize the current unbalance in the primary we use delta winding in the primary So delta / star transformer is used for lighting loads.

Why star delta starter is preferred with induction motor?

Description : Why star delta starter is preferred with induction motor?

Last Answer : Star delta starter is preferred with induction motor due to following reasons: Starting current is reduced 3-4 times of the direct current due to which voltage drops and hence it causes less ... caused. In addition, starting torque is increased and it prevents the damage of motor winding.

In a three phase transformer, if the primary side is connected in star and secondary side is connected in delta, what is the angle difference between phase voltage in the two cases. (A) delta side lags by -30°. (B) star side lags by -30°. (C) delta side leads by 30°. (D) star side leads by -30°.

Description : In a three phase transformer, if the primary side is connected in star and secondary side is connected in delta, what is the angle difference between phase voltage in the two cases. (A) delta side lags by -30°. (B) star side lags by -30°. (C) delta side leads by 30°. (D) star side leads by -30°.

Last Answer : Ans: C This is vector group and has +30° displacement. Therefore, delta side leads by +30°.

Electrostatic type instruments are mainly used for measurement of: a) Heavy currents b) Low currents c) Low voltages d) High voltages

Description : Electrostatic type instruments are mainly used for measurement of: a) Heavy currents b) Low currents c) Low voltages d) High voltages

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When a resistor is used as a shunt and is connected in parallel with a meter movement coil, it will provide _____________. A. a measurement of circuit resistance B. an increased accuracy of approximately 1.5 percent C. an extended meter range D. none of the above

Description : When a resistor is used as a shunt and is connected in parallel with a meter movement coil, it will provide _____________. A. a measurement of circuit resistance B. an increased accuracy of approximately 1.5 percent C. an extended meter range D. none of the above

Last Answer : Answer: C

In order to increase its range of measurement, a resistance would be placed in series with which of the following instruments? A. DC voltmeter B. DC ammeter C. frequency meter D. power factor meter

Description : In order to increase its range of measurement, a resistance would be placed in series with which of the following instruments? A. DC voltmeter B. DC ammeter C. frequency meter D. power factor meter

Last Answer : Answer: A

What is the equation for resistance measurement of PT 100 thermocouple?

Description : What is the equation for resistance measurement of PT 100 thermocouple? 

Last Answer : °C = (R-100) / 0.39  

What is the purpose of rotor AC Impedance measurement?

Description : What is the purpose of rotor AC Impedance measurement?

Last Answer : Periodic measurement of rotor impedance using an AC power supply is another means of detecting the presence of shorted turns in a rotor winding. Impedance measurement is more sensitive than the ... single shorted turn opposes the MMF of the entire coil, thus greatly reducing the reactance. 

What is the necessity of shaft voltage measurement?

Description : What is the necessity of shaft voltage measurement?

Last Answer : It is to observe insulation of bearing 6 & 7 and hydrogen seal assembly. It requires minimum leakage current (<100mA) through bearings and shaft seals to avoid pitting of bearings. ... >100mA, clean the insulation provided between bearing pedestal and seal housing with earth. 

What should be the frequency of measurement of earth resistivity?

Description : What should be the frequency of measurement of earth resistivity?

Last Answer : As per IS: 3043, 1987, measurement of earth resistivity should be carried out annually or biannually and value should be recorded. 

What is the instrument name used for accurate measurement of IP?

Description : What is the instrument name used for accurate measurement of IP? 

Last Answer : Infra red spectro photometer.  

State some elements of flow measurement.

Description : State some elements of flow measurement. 

Last Answer : Orifice, Venturi tubes, flowrator (rotameter) etc.  

State some elements of pressure measurement.

Description : State some elements of pressure measurement. 

Last Answer : Manometer, Diaphragm gauges, Bellows, Strain gauges etc.  

Draw a neat sketch and explain the use of CT and PT for measurement of power in a single-phase circuit?

Description : Draw a neat sketch and explain the use of CT and PT for measurement of power in a single-phase circuit?

Last Answer : If wattmeter of proper range is not available or if voltage and current ranges are high we can usr CT and PT of suitable ratio. Connect the CT and PT as shown in figure. The reading of wattmeter can be multiplied by the ratio to get the actual power.   

What are the limits of vibration measurement for motors?

Description : What are the limits of vibration measurement for motors?

Last Answer : 50 microns for displacement and 5 mm/second for velocity.

In dielectric measurement, the dielectric loss is proportional to a) F b) V c) I d) Vsqr

Description : In dielectric measurement, the dielectric loss is proportional to a) F b) V c) I d) Vsqr

Last Answer : Ans: Vsqr

The two watt meters measurement the ratio of two meter readings is –(1-sqrt3):( 1+sqrt3) then the power factor is a) 1 b) 0.866 c) 0.707 d) 0

Description : The two watt meters measurement the ratio of two meter readings is –(1-sqrt3):( 1+sqrt3) then the power factor is a) 1 b) 0.866 c) 0.707 d) 0

Last Answer : Ans: 0.707

What is the derivative of y = tan 1/2 x^3?

Description : What is the derivative of y = tan 1/2 x^3?

Last Answer : 3xraised2/(2*cos((xraised3)/2)raised2) Now work it back and see how that happened.

Can a fair skinned person still get a tan when using a high SPF all over?

Description : Can a fair skinned person still get a tan when using a high SPF all over?

Last Answer : Do what you want, but sunscreen may help avoid sunburn, but doesn't usually help with skin cancer. If you really want a tan, you are best off working up to it. Get out into the sun for a limited time ... up and now I can be outside in just shorts and flip-flops for a couple hours and I don't burn.

Do I suit being pale or tan better?

Description : Do I suit being pale or tan better?

Last Answer : answer:I always think pale skin is better, personally… But I will say that tanned, you look like Guy Pearce in Memento. That’s at least partially the hair, though.

Why won't my neck tan? (This is bound to be the most pressing question ever asked on ask-public...:P)

Description : Why won't my neck tan? (This is bound to be the most pressing question ever asked on ask-public...:P)

Last Answer : answer:Sounds like you may be developing a mild case of Red Neck-itus Have you noticed any of the following symptoms? -teeth loosening? -craving for fried everything? -unexplainable new ... I recommend that all single string musical instruments be removed from your life immediately. Good luck!

Still getting a tan despite applying SPF. Am I going to be a leather bag when I'm 40?

Description : Still getting a tan despite applying SPF. Am I going to be a leather bag when I'm 40?

Last Answer : I worked outside all the time as a kid, and I still spend a lot of times outdoors. I turn darker in the summer, but my skin has held up well. If you’re using sunscreen you should be okay.

How do I keep my tan from getting darker?

Description : How do I keep my tan from getting darker?

Last Answer : Suntan lotion. SPF 15 will do the trick. Or, clothing.

Can a blue-eyed swede who stays indoors have tan skin? How?

Description : Can a blue-eyed swede who stays indoors have tan skin? How?

Last Answer : It sounds like a symptom of liver damage to me. And it sounds advanced. What does the doctor say? I’ve also heard of this happening to people when they drink a lot of carrot juice.