What is meant by partial discharge? How can be tested?

What is meant by partial discharge? How can be tested?  
by

1 Answer

Answer :

Partial discharges are electrical sparks, which occur in gas voids within the insulation when the voltage is high enough. The discharges are partial since there is some insulation remaining to prevent a complete breakdown. Partial discharge can erode the insulation and therefore contribute to insulation ageing.

This can be tested by electromagnetic probe, which is a detector that is sensitive to the radio frequency signals produced by the partial discharges within the winding. With this probe test it is possible to locate specific sites of deterioration within the winding when the winding is energized.  
by

Related questions

Discharge switches are often located on hand-driven meggers. The purpose of these switches is to discharge capacitive charges stored in the _____________. A. megger hand generator B. megger movement coils C. tested equipment while conducting test D. tested equipment after testing

Description : Discharge switches are often located on hand-driven meggers. The purpose of these switches is to discharge capacitive charges stored in the _____________. A. megger hand generator B. megger movement coils C. tested equipment while conducting test D. tested equipment after testing

Last Answer : Answer: D

India’s newly built and tested missile ‘Astra’ is meant for—

Description : India’s newly built and tested missile ‘Astra’ is meant for—

Last Answer : Air to air strike

An emergency generator, driven by an internal combustion engine, shall be tested under load for a minimum of 2 hours at least once every _____________. A. week B. 2 weeks C. month D. 3 months

Description : An emergency generator, driven by an internal combustion engine, shall be tested under load for a minimum of 2 hours at least once every _____________. A. week B. 2 weeks C. month D. 3 months

Last Answer : Answer: C

An open shunt field in a direct current machine may be located by connecting the field circuit to an external power source, equal to the rated field voltage or less, and tested with a voltmeter from _____________. A. one line terminal to each coil lead in succession B. one field coil to each adjacent field coil in turn C. any suitable ground to any available line lead D. any field pole to each field coil lead

Description : An open shunt field in a direct current machine may be located by connecting the field circuit to an external power source, equal to the rated field voltage or less, and tested with a voltmeter from ... C. any suitable ground to any available line lead D. any field pole to each field coil lead

Last Answer : Answer: A

If reading AC current with the illustrated device and unsure of the range as a precaution , the first step should be to _________. EL-0047 A. secure power and test for voltage B. disconnect the lead to be tested and connect the meter in series C. connect the meter to measure resistance and use Ohm's law to calculate current D. unable to safely measure current with the device

Description : If reading AC current with the illustrated device and unsure of the range as a precaution , the first step should be to _________. EL-0047 A. secure power and test for voltage B. disconnect the ... resistance and use Ohm's law to calculate current D. unable to safely measure current with the device

Last Answer : Answer: A

When used for taking resistance measurements, a volt-ohm-milliammeter is normally powered by _____________. A. a hand cranked generator B. internal storage batteries C. the current in the circuit being tested D. a step down transformer

Description : When used for taking resistance measurements, a volt-ohm-milliammeter is normally powered by _____________. A. a hand cranked generator B. internal storage batteries C. the current in the circuit being tested D. a step down transformer

Last Answer : Answer: B

A capacitor is to be tested with a megohmmeter. If the meter is connected to a shorted capacitor, the meter pointer should _____________. A. immediately swing to the maximum resistance value B. deflect to zero and remain at that position C. swing to a high reading and gradually decrease D. swing to zero then gradually increase with slight pointer movements down scale

Description : A capacitor is to be tested with a megohmmeter. If the meter is connected to a shorted capacitor, the meter pointer should _____________. A. immediately swing to the maximum resistance value ... and gradually decrease D. swing to zero then gradually increase with slight pointer movements down scale

Last Answer : Answer: B

A suspected 'open' in a motor field can be tested by using a/an ____________. A. potentiometer B. megger C. wattmeter D. ammeter

Description : A suspected 'open' in a motor field can be tested by using a/an ____________. A. potentiometer B. megger C. wattmeter D. ammeter

Last Answer : Answer: B

A capacitor can be tested using a megohmmeter or an ohmmeter. If the meter is connected to a shorted capacitor, the meter pointer should _____________. A. immediately swing to the maximum resistance value for the capacitor B. first swing quickly to 'zero', then gradually move up the scale as the capacitor charges C. immediately deflect to and remain at zero D. immediately swing to a high reading and then gradually decrease

Description : A capacitor can be tested using a megohmmeter or an ohmmeter. If the meter is connected to a shorted capacitor, the meter pointer should _____________. A. immediately swing to the maximum resistance ... deflect to and remain at zero D. immediately swing to a high reading and then gradually decrease

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

The insulation resistance of electric equipment and machinery should be tested for the lowest normal insulation values _____________. A. immediately after shutting down the machine B. every time the brush rigging is adjusted C. immediately after starting up the machine D. every 30 days whether the machine is in use or not

Description : The insulation resistance of electric equipment and machinery should be tested for the lowest normal insulation values _____________. A. immediately after shutting down the machine B. every time the brush rigging is ... starting up the machine D. every 30 days whether the machine is in use or not

Last Answer : Answer: A

When troubleshooting electronic equipment, you should use a high impedance multimeter ________________. A. to prevent excess current flow through the meter that would damage it B. for AC measurements only and a low resistance meter for DC measurements C. whenever a low impedance meter is not available, regardless of the components being tested D. so as not to load down the circuit and obtain erroneous voltage readings

Description : When troubleshooting electronic equipment, you should use a high impedance multimeter ________________. A. to prevent excess current flow through the meter that would damage it B. for AC measurements only ... being tested D. so as not to load down the circuit and obtain erroneous voltage readings

Last Answer : Answer: D

A resistance in a circuit of unknown value is to be tested using the voltmeter/ammeter method. Therefore, the meters should be connected with _____________. A. both meters in series with the resistance B. both meters in parallel with the resistance C. the ammeter in series and the voltmeter in parallel with the resistance D. the ammeter in parallel and the voltmeter in series with the resistance

Description : A resistance in a circuit of unknown value is to be tested using the voltmeter/ammeter method. Therefore, the meters should be connected with _____________. A. both meters in series with the ... parallel with the resistance D. the ammeter in parallel and the voltmeter in series with the resistance

Last Answer : Answer: C

Which of the listed conditions will occur if dirt and grease are allowed to accumulate between the commutator segments of a motor? A. A partial short circuit. B. A dead short circuit. C. Misalignment of the motor shaft. D. Overspeeding of the motor.

Description : Which of the listed conditions will occur if dirt and grease are allowed to accumulate between the commutator segments of a motor? A. A partial short circuit. B. A dead short circuit. C. Misalignment of the motor shaft. D. Overspeeding of the motor.

Last Answer : Answer: A

If your multimeter gives a reading in ohms when testing each end of each conductor of a three-conductor cable, this indicates ______________. A. continuity of the conductor B. an infinite resistance C. the presence of a partial ground D. that the conductor is not short circuited

Description : If your multimeter gives a reading in ohms when testing each end of each conductor of a three-conductor cable, this indicates ______________. A. continuity of the conductor B. an infinite resistance C. the presence of a partial ground D. that the conductor is not short circuited

Last Answer : Answer: A

A wattmeter is used to determine ____________. A. the power being consumed by electrical equipment B. partial circuit resistance C. current flowing in a circuit D. voltage existing between two points in a circuit

Description : A wattmeter is used to determine ____________. A. the power being consumed by electrical equipment B. partial circuit resistance C. current flowing in a circuit D. voltage existing between two points in a circuit

Last Answer : Answer: A

An ammeter should be used to measure ___________. A. the voltage between two points in a circuit B. circuit continuity C. current flow in a circuit D. total or partial circuit resistance

Description : An ammeter should be used to measure ___________. A. the voltage between two points in a circuit B. circuit continuity C. current flow in a circuit D. total or partial circuit resistance

Last Answer : Answer: C

For practical purposes, in a simple series circuit, the source voltage will be dropped across one resistor if it has ______________. A. half the resistance of the other resistor B. a resistance equal to the other C. at least ten times the resistance of the other D. a partial short circuit

Description : For practical purposes, in a simple series circuit, the source voltage will be dropped across one resistor if it has ______________. A. half the resistance of the other resistor B. a resistance equal to the other C. at least ten times the resistance of the other D. a partial short circuit

Last Answer : Answer: C

With both ends of a three conductor cable disconnected and arranged without the conductors touching each other, an ohmmeter reading of 'zero' ohms between the ends of one conductor would indicate _____________. A. continuity B. a partial ground C. the resistance is infinite D. a short circuit

Description : With both ends of a three conductor cable disconnected and arranged without the conductors touching each other, an ohmmeter reading of 'zero' ohms between the ends of one conductor would indicate _____________. A. continuity B. a partial ground C. the resistance is infinite D. a short circuit

Last Answer : Answer: A

If you disconnect and arrange both ends of a three conductor cable, without any contact between the individual conductors, an indicated ohmic value between the ends of a single conductor would indicate ______________. A. continuity of the conductor B. an infinite resistance C. the presence of a partial ground D. that the conductor is not short circuited

Description : If you disconnect and arrange both ends of a three conductor cable, without any contact between the individual conductors, an indicated ohmic value between the ends of a single conductor would indicate ... resistance C. the presence of a partial ground D. that the conductor is not short circuited

Last Answer : Answer: A

The illustrated circuits are used to measure ___________. EL-0024 A. resistance B. gauss or magnetic field strength C. battery discharge rate in Amp-hours D. current

Description : The illustrated circuits are used to measure ___________. EL-0024 A. resistance B. gauss or magnetic field strength C. battery discharge rate in Amp-hours D. current

Last Answer : Answer: A

Brush sparking during commutation may be caused by ________. A. eddy currents in the armature core B. laminations in the generator field pieces C. induced current opposite to coil inductance D. coil inductance discharge occurring at commutation

Description : Brush sparking during commutation may be caused by ________. A. eddy currents in the armature core B. laminations in the generator field pieces C. induced current opposite to coil inductance D. coil inductance discharge occurring at commutation

Last Answer : Answer: D

Before servicing the device indicated as 'A' in panels #1 and #3 of the illustration, the device labeled 'CT' must __________. EL-0003 A. have the disconnected leads taped to prevent short circuiting. B. only be connected to multimeter on the ammeter setting C. be short circuited D. have one lead grounded to discharge static electricity for the prevention of damage to electronic components

Description : Before servicing the device indicated as 'A' in panels #1 and #3 of the illustration, the device labeled 'CT' must __________. EL-0003 A. have the disconnected leads taped to prevent ... D. have one lead grounded to discharge static electricity for the prevention of damage to electronic components

Last Answer : Answer: C

When a battery-charging panel is being used, the batteries will discharge if _____________. A. DC voltage is supplied B. the polarity is reversed C. the voltage fluctuates D. too little current is supplied

Description : When a battery-charging panel is being used, the batteries will discharge if _____________. A. DC voltage is supplied B. the polarity is reversed C. the voltage fluctuates D. too little current is supplied

Last Answer : Answer: B

At high discharge rates, nickel-cadmium storage batteries are superior to lead-acid batteries because they __________. A. require fewer cells for the same voltage and less mounting space B. are able to produce higher voltages and do not have to be charged as often C. can be charged and discharged many times without much damage D. have no individual cells to replace at the end of useful life

Description : At high discharge rates, nickel-cadmium storage batteries are superior to lead-acid batteries because they __________. A. require fewer cells for the same voltage and less mounting space B. are able to ... times without much damage D. have no individual cells to replace at the end of useful life

Last Answer : Answer: C

Nickel-cadmium batteries are superior to lead-acid batteries at high discharge rates because they _______________. A. deliver a large amount of power and can be recharged in a shorter time B. need fewer cells in connected series and less mounting space C. have higher output voltages and require no maintenance D. all of the above

Description : Nickel-cadmium batteries are superior to lead-acid batteries at high discharge rates because they _______________. A. deliver a large amount of power and can be recharged in a shorter time B. need ... less mounting space C. have higher output voltages and require no maintenance D. all of the above

Last Answer : Answer: A

Under which of the following conditions will a lead-acid battery be given a 'test discharge'? A. To determine its capacity. B. Whenever a cell cannot be brought within 10 points of full charge specific gravity. C. When one or more cells is found to have less than normal voltage after an equalizing charge. D. All of the above.

Description : Under which of the following conditions will a lead-acid battery be given a 'test discharge'? A. To determine its capacity. B. Whenever a cell cannot be brought within 10 points of full charge ... cells is found to have less than normal voltage after an equalizing charge. D. All of the above.

Last Answer : Answer: D

During discharge of a lead-acid storage battery, which of the following actions occurs? A. The acid becomes stronger. B. Both plates change chemically to ammonium chloride. C. The acid becomes weaker. D. Hydrogen gas is liberated.

Description : During discharge of a lead-acid storage battery, which of the following actions occurs? A. The acid becomes stronger. B. Both plates change chemically to ammonium chloride. C. The acid becomes weaker. D. Hydrogen gas is liberated.

Last Answer : Answer: C

The specific gravity of the electrolyte solution in a lead acid battery _____________. A. is not effected during charging B. remains the same during discharge C. would read close to 1.830 when discharged D. gives an indication of the state of charge of the battery

Description : The specific gravity of the electrolyte solution in a lead acid battery _____________. A. is not effected during charging B. remains the same during discharge C. would read close to 1.830 when discharged D. gives an indication of the state of charge of the battery

Last Answer : Answer: D

When you are making a high potential test on a piece of repaired electrical machinery, a rise in leakage current indicates ____________. A. good insulation B. bad insulation C. high insulation power factor D. a high slot discharge factor

Description : When you are making a high potential test on a piece of repaired electrical machinery, a rise in leakage current indicates ____________. A. good insulation B. bad insulation C. high insulation power factor D. a high slot discharge factor

Last Answer : Answer: B

The purpose of the capacitor within component 'B' of the circuit shown in the illustration is to ____________. EL-0081 A. prolong the life of the component's contacts B. discharge the neon within the envelope C. counteract the inductive reactance in the circuit D. store power to operate the circuit should 'D' open

Description : The purpose of the capacitor within component 'B' of the circuit shown in the illustration is to ____________. EL-0081 A. prolong the life of the component's contacts B. discharge the neon within ... the inductive reactance in the circuit D. store power to operate the circuit should 'D' open

Last Answer : Answer: A

What is material used in making non-linear resistor & purpose of it in field discharge resistor?

Description : What is material used in making non-linear resistor & purpose of it in field discharge resistor?  

Last Answer : Silicon carbide materials used for making non-linear resistor. The purpose of this resistor is to avoid surge voltage when field breaker opens. These resistors are connected in parallel to the main field winding (Rotor). 

How carona discharge is prevented in generator insulation?

Description : How carona discharge is prevented in generator insulation?

Last Answer : To prevent carona discharges between insulation and the wall of the slot, the insulation in slot portion is coated with semi conducting varnish. This eliminates the formation of creepage sparks during operation and during HV test. 

My personal space and safety has been tested several times the past few months. What can I do to feel more safe?

Description : My personal space and safety has been tested several times the past few months. What can I do to feel more safe?

Last Answer : Carry a gun where people can see it.

Will more people be inspired to get the COVID vaccine now that golfer Jon Rahm has tested positive? For possibly the second time?

Description : Will more people be inspired to get the COVID vaccine now that golfer Jon Rahm has tested positive? For possibly the second time?

Last Answer : If hundreds of thousands of deceased people didn’t do the trick, some golfer won’t either.

How much money did you spend since last year getting tested for Covid and also getting the vaccination shots?

Description : How much money did you spend since last year getting tested for Covid and also getting the vaccination shots?

Last Answer : Zero ! Haven’t had a COVID-19 test and vaccination were free. Local CVS has been offering No cost to you – -COVID-19 Tests.

People born before 1980: do you remember the first time you had your cholesterol tested?

Description : People born before 1980: do you remember the first time you had your cholesterol tested?

Last Answer : Yes. 2012. Numbers were spectacularly good.

Has anyone had their telomeres tested?

Description : Has anyone had their telomeres tested?

Last Answer : What kind of a test is it? What is it for?

Have you had your DNA tested?

Description : Have you had your DNA tested?

Last Answer : Yes. I had it done thru Ancestry.com. It was regularly $100 but I got a cyber Monday sale – $70 I think. I liked it and from what I know about my relatives, it was accurate.

Did you take your kids for routine allergy testing? Were you ever tested?

Description : Did you take your kids for routine allergy testing? Were you ever tested?

Last Answer : answer:No. No. My daughter says she’s allergic to strawberries, but I’ve never witnessed any kind of reaction. I’ll just take her word for it.

Anyone have a tried and tested recipe for cauliflower soup?

Description : Anyone have a tried and tested recipe for cauliflower soup?

Last Answer : I always go to Food Network;charset=UTF-8 now to search for new recipes and you can read other cooks reviews and tips for shortcuts and making some recipes even better.

Would you change brands if you knew a company tested its products on animals?

Description : Would you change brands if you knew a company tested its products on animals?

Last Answer : Years ago I would have said it doesn’t make a difference to me. But they have got better testing methods today. I wouldn’t use anything tested on animals. I’ll write a few letters and if necessary switch a few products. Thanks for the list.

How would a 'non scientist' propose a hypothesis in such a way that it would be considered and tested by scientists?

Description : How would a 'non scientist' propose a hypothesis in such a way that it would be considered and tested by scientists?

Last Answer : Are you seeking funding? Is that why you want to present the idea? Or, are you seeking help with setting up the experiment?

I had an eye exam done three years ago (I used to have a pair of glasses for seeing the blackboard), do I need to have my eyes tested again?

Description : I had an eye exam done three years ago (I used to have a pair of glasses for seeing the blackboard), do I need to have my eyes tested again?

Last Answer : In the USA, prescriptions are generally valid for only 1 year. I’m not sure of the laws in Canada, though.

Computer gurus, can a WordPress site be developed and tested on my local machine before uploading?

Description : Computer gurus, can a WordPress site be developed and tested on my local machine before uploading?

Last Answer : answer:Yes, you would just need a local web server to process the PHP and handle the database (mysql). If you're on a PC, try WAMP - which I haven't used, but understand is good. ... can look at a development copy for approval without you putting everything on their server right away. Good luck.

Have you had your DNA tested?

Description : Have you had your DNA tested?

Last Answer : answer:I haven't had my DNA tested although I think the results would be informative and potentially interesting. I worry about this sort of testing because of the potential for insurance companies to ... happen (it may already happen) and I hope someone with more info will answer this question.

Have you tested your PC yet?

Description : Have you tested your PC yet?

Last Answer : Yes. Clean. Since this exploit has been identified for ages now and all the big Anti-Virus suppliers were aware of it, I was sure I’d be fine. But in the abundance of caution, I did check. Still, good warning for those that didn’t get the memo.