Why is a Megger used for insulation test and not a multi meter?

Why is a Megger used for insulation test and not a multi meter?
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Answer :

With a megger,a voltage of not less than 500 volts DC is used for testing the insulation resistance of windings. With a multi-meter, the voltage used is not more than 3-volts DC. Megger uses high impedance testing and is therefore more accurate than a multi-meter
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Related questions

A generator has been exposed to water and is being checked for its safe operation. Therefore, it is necessary to _______________. A. check for shorted coils with a growler B. take moisture readings with a hydrometer C. test insulation values with a megger D. ground the commutator, or slip rings and run it at half load for 12 hours

Description : A generator has been exposed to water and is being checked for its safe operation. Therefore, it is necessary to _______________. A. check for shorted coils with a growler B. take moisture readings with a ... a megger D. ground the commutator, or slip rings and run it at half load for 12 hours

Last Answer : Answer: C

What is the difference between megger test equipment and contact resistance meter test instruments?

Description : What is the difference between megger test equipment and contact resistance meter test instruments?

Last Answer : Megger test equipment used to measure cable electric resistance, conductor continuity, phase identification. Contact resistance meter test instruments used to measure low resistance like relays, contactors.

What happens to insulation when temperature rises?

Description : What happens to insulation when temperature rises?

Last Answer : For insulators, an increase in temperature will cause their resistance to decrease -which is why excessive temperature is often the main reason why insulation fails

Which of the conditions listed will indicate the need to clean the insulation on the windings of an electric motor? A. Higher than normal operating temperature. B. Excessive vibration at normal speed. C. Sparking at the brushes. D. High megger readings.

Description : Which of the conditions listed will indicate the need to clean the insulation on the windings of an electric motor? A. Higher than normal operating temperature. B. Excessive vibration at normal speed. C. Sparking at the brushes. D. High megger readings.

Last Answer : Answer: A

Routine maintenance of dry-type transformers should include ______________. A. preventing the entrance of water from broken pipe lines steam lines B. keeping protective surfaces and insulating bushings free of dirt and conductive debris C. periodic testing of insulation resistance with a megger D. all of the above

Description : Routine maintenance of dry-type transformers should include ______________. A. preventing the entrance of water from broken pipe lines steam lines B. keeping protective surfaces and insulating bushings free of ... debris C. periodic testing of insulation resistance with a megger D. all of the above

Last Answer : Answer: D

Which of the listed conditions could indicate the need for cleaning electrical insulation? A. Low ambient temperature B. Low operating temperature C. High dielectric strength D. Low megger readings

Description : Which of the listed conditions could indicate the need for cleaning electrical insulation? A. Low ambient temperature B. Low operating temperature C. High dielectric strength D. Low megger readings

Last Answer : Answer: D

The need for insulation cleaning may be determined by _____. A. visual inspection for dirt accumulation B. high megger readings C. low operating temperature D. the time period since the last cleaning

Description : The need for insulation cleaning may be determined by _____. A. visual inspection for dirt accumulation B. high megger readings C. low operating temperature D. the time period since the last cleaning

Last Answer : Answer: A

When troubleshooting motor controllers, a shorted relay or contactor coil is often indicated by _______________. A. a resistance reading of 'infinity' on an ohmmeter B. charred insulation and/or a blown control fuse C. a reading of 'zero' on a megger from one of the coil's leads to ground D. a higher-than-normal voltage reading across the winding

Description : When troubleshooting motor controllers, a shorted relay or contactor coil is often indicated by _______________. A. a resistance reading of 'infinity' on an ohmmeter B. charred insulation and/or a blown ... of the coil's leads to ground D. a higher-than-normal voltage reading across the winding

Last Answer : Answer: B

Electrical machinery insulation will break down more rapidly due to _________________. A. low loading of motors and generators B. frequent megger testing C. high temperatures and vibration D. high operating frequencies

Description : Electrical machinery insulation will break down more rapidly due to _________________. A. low loading of motors and generators B. frequent megger testing C. high temperatures and vibration D. high operating frequencies

Last Answer : Answer: C

Routine maintenance of a ship's service alternator should include ______________. A. changing the pedestal bearing insulation yearly B. megger testing of all rectifying diodes C. lubricating excitation slip rings D. periodic cleaning of the air filters or screens

Description : Routine maintenance of a ship's service alternator should include ______________. A. changing the pedestal bearing insulation yearly B. megger testing of all rectifying diodes C. lubricating excitation slip rings D. periodic cleaning of the air filters or screens

Last Answer : Answer: D

What is a normal indication on a megger when checking insulation?

Description : What is a normal indication on a megger when checking insulation?

Last Answer : Infinity.

What is the procedure for using a megger to check the insulation of a conductor?

Description : What is the procedure for using a megger to check the insulation of a conductor?

Last Answer : Connect one lead to the insulation and one lead to the conductor. Turn the handcrank until it starts to slip. Note the reading

What is the normal indication on a megger when checking insulation?

Description : What is the normal indication on a megger when checking insulation?

Last Answer : infinity

A megger is to measure insulation resistance of a cable. The cable should be connected to

Description : A megger is to measure insulation resistance of a cable. The cable should be connected to   (a) Battery (b) DC supply (c) AC supply (d) No supply  

Last Answer : majorly in DC as well as AC......but ans is Battery

To measure insulation resistance of equipments of voltage rating upto 440 V the megger generator must generate...

Description : To measure insulation resistance of equipments of voltage rating upto 440 V the megger generator must generate   (a) 220 V (b) 440 V (c) 500 V (d) None of these 

Last Answer : 500 V

A 0-10 mA PMMC ammeter reads 5mA in a circuit; its bottom control spring snaps out suddenly the meter will now read. a) 5mA b) 10mA c) 2.5mA d) 0

Description : A 0-10 mA PMMC ammeter reads 5mA in a circuit; its bottom control spring snaps out suddenly the meter will now read. a) 5mA b) 10mA c) 2.5mA d) 0

Last Answer : Ans: 0

What is an AVO meter?

Description : What is an AVO meter?

Last Answer : The Avometer was a British brand of multimeter, latterly owned by Megger. It is often called simply an AVO and derives its name from the first letter of the words amperes, volts, ohms

A multipurpose instrument for measuring current, potential difference and resistance is a) Ohmmeter b) Astatic galvanometer c) Rheostat d) AVO Meter

Description : A multipurpose instrument for measuring current, potential difference and resistance is a) Ohmmeter b) Astatic galvanometer c) Rheostat d) AVO Meter

Last Answer : d) AVO Meter

Digital version of an AVO meter is known as a) Digital Ohmmeter b) Multimeter c) Digital Multimeter d) None of these

Description : Digital version of an AVO meter is known as a) Digital Ohmmeter b) Multimeter c) Digital Multimeter d) None of these

Last Answer : c) Digital Multimeter

The SI unit of charge is: (a) Meter (b) Ampere (c) Coulomb (d) Volt

Description : The SI unit of charge is: (a) Meter (b) Ampere (c) Coulomb (d) Volt

Last Answer : (c) Coulomb

kWh meter is the electric meter that measures the amount of electrical _________ in kWh that

Description : kWh meter is the electric meter that measures the amount of electrical _________ in kWh that was consumed in the house.  (A) Energy (B) Current (C) Voltage (D) None of the above

Last Answer : kWh meter is the electric meter that measures the amount of electrical Energy in kWh that was consumed in the house. 

A useful instrument for checking A.C. motor performance by measuring possible unbalanced currents is the _____________. A. hand or battery-operated megger B. vibrating-reed frequency meter C. hook-on voltmeter-ammeter D. D'Arsonval iron-vane probe

Description : A useful instrument for checking A.C. motor performance by measuring possible unbalanced currents is the _____________. A. hand or battery-operated megger B. vibrating-reed frequency meter C. hook-on voltmeter-ammeter D. D'Arsonval iron-vane probe

Last Answer : Answer: C

Different between megger and contact resistance meter?

Description : Different between megger and contact resistance meter?

Last Answer : Answers: Megger used to measure cable resistance, conductor continuity, phase identification where as contact resistance meter used to measure low resistance like relays ,contactors.

Different between megger and contact resistance meter?

Description : Different between megger and contact resistance meter?

Last Answer :  Megger used to measure cable resistance, conductor continuity, phase identification where as contact resistance meter used to measure low resistance like relays, contactors.

In preparing to take insulation resistance readings on a main generator, the windings should be grounded for about 15 minutes prior to the test to _____________. A. allow accurate zeroing of the meter B. help the windings to cool to ambient temperature C. release any residual capacitive charge from the windings D. help the windings to cool to the same temperature as the ground test connection

Description : In preparing to take insulation resistance readings on a main generator, the windings should be grounded for about 15 minutes prior to the test to _____________. A. allow accurate zeroing of the meter ... the windings D. help the windings to cool to the same temperature as the ground test connection

Last Answer : Answer: C

Before using a volt-ohmmeter to measure resistance readings, you should _____________. A. replace all batteries B. test the insulation resistance of the leads C. make sure the test leads do not touch D. hold the leads together and 'zero' the meter

Description : Before using a volt-ohmmeter to measure resistance readings, you should _____________. A. replace all batteries B. test the insulation resistance of the leads C. make sure the test leads do not touch D. hold the leads together and 'zero' the meter

Last Answer : Answer: D

How do you test reverse power trip, high current trip, preferential trip?

Description : How do you test reverse power trip, high current trip, preferential trip?

Last Answer : Reverse power trip - refer answer for question 11. Also ask E/O. High current (over load trip) - Set your overload relay high current trip setting to say 75% of the rated current. Run the ... loads to overload the generator. Preferential trip will trip all the non-critical loads. Also ask E/O.

How do you test reverse power trip?

Description : How do you test reverse power trip?

Last Answer : When two generators are running in parallel and one generator can carry the load, reverse power trip can be tested by load shifting using governor control. When the load has shifted sufficiently and the off ... (using the test push button on the relay) to see if it initiates a trip signal.

What are the test and measuring instrument required in an Electrical depots?

Description : What are the test and measuring instrument required in an Electrical depots?

Last Answer : Ans. Following are the test and measuring instruments required in an Electrical depots. a. Test lamp b. Line Tester c. Continuity tester d. Volt meter e. Ammeter f. Earth megger g. Megger h. Lux meter i. Power analyzer j. Infrared thermometer

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

As a general rule, the first troubleshooting action to be taken in checking faulty electric control devices is to _____________. A. draw a one line diagram of the circuitry B. test all fuses and measure the line voltage C. take megger readings D. insulate the apparatus from ground

Description : As a general rule, the first troubleshooting action to be taken in checking faulty electric control devices is to _____________. A. draw a one line diagram of the circuitry B. test all fuses and measure the line voltage C. take megger readings D. insulate the apparatus from ground

Last Answer : Answer: B

Megger is used to test _________.

Description : Megger is used to test _________. A. Insulation B. Current C. Capacitance D. None of these

Last Answer : Megger is used to test Capacitance.

When a megohmmeter is being used on a alternating current machine, the meter pointer will dip toward 'zero' and then gradually rise to the true resistance value if the motor insulation is _____________. A. grounded B. good C. shorted D. dirty

Description : When a megohmmeter is being used on a alternating current machine, the meter pointer will dip toward 'zero' and then gradually rise to the true resistance value if the motor insulation is _____________. A. grounded B. good C. shorted D. dirty

Last Answer : Answer: B

On some electrical generating equipment one outboard bearing pedestal is insulated from the bedplate. To check this insulation with the machine assembled you should use a____________. A. millivolt meter and a jumper B. ohmmeter C. megohm meter D. high potential tester

Description : On some electrical generating equipment one outboard bearing pedestal is insulated from the bedplate. To check this insulation with the machine assembled you should use a____________. A. millivolt meter and a jumper B. ohmmeter C. megohm meter D. high potential tester

Last Answer : Answer: A

On some electrical generating equipment one outboard bearing pedestal is insulated from the bedplate. To check this insulation with the machine assembled you should use a____________. A. ohmmeter with the machine secured B. millivolt meter and a jumper with the machine running C. megohm meter with the machine running D. voltmeter and ampmeter with the machine running

Description : On some electrical generating equipment one outboard bearing pedestal is insulated from the bedplate. To check this insulation with the machine assembled you should use a____________. A. ohmmeter with the ... C. megohm meter with the machine running D. voltmeter and ampmeter with the machine running

Last Answer : Answer: B

Which of the listed statements is correct when using an analog multimeter as an ohmmeter? A. The pointer should be adjusted to zero each time a new resistance range is selected. B. The pointer will move to infinity when the meter is not in use. C. Ohmmeters are not sufficiently sized to measure conductor insulation resistance. D. All of the above.

Description : Which of the listed statements is correct when using an analog multimeter as an ohmmeter? A. The pointer should be adjusted to zero each time a new resistance range is selected. B. The ... C. Ohmmeters are not sufficiently sized to measure conductor insulation resistance. D. All of the above.

Last Answer : Answer: D

Insulation resistance is measured by which meter?

Description : Insulation resistance is measured by which meter?

Last Answer : megger

How to check Capacitor with use of Multi meter.

Description : How to check Capacitor with use of Multi meter.

Last Answer :  Most troubles with Capacitors either open or short.  An ohmmeter (multi meter) is good enough. A shorted Capacitor will clearly show very low resistance. A open Capacitor will not show any ... momentarily can give a weak spark. To know the value and other parameters, you need better instruments

A digital multi meter is an example of an embedded system for A. Data communication B. Monitoring C. Control D. All of these

Description : A digital multi meter is an example of an embedded system for A. Data communication B. Monitoring C. Control D. All of these

Last Answer : B. Monitoring

A digital multi meter is an example of an embedded system for A. Data communication B. Monitoring C. Control D. All of these E. None of these

Description : A digital multi meter is an example of an embedded system for A. Data communication B. Monitoring C. Control D. All of these E. None of these

Last Answer : B. Monitoring 

5) An iron ring of mean circumference of 80 cm is uniformly wound with 500 turns of wire. Calculate the value of flux density that a current of 1 A would produce in the ring. Assume relative permeability 1400.

Description : Please ripley me due to emergency

Last Answer : To calculate the flux density in the ring, you need to use the following formula: B = (μ * I * N) / (2 * π * r) where: B is the flux density in the ring (in teslas) μ is the relative permeability ... 2 * π * 0.127 m) = 0.53 T So the flux density in the ring would be approximately 0.53 teslas.

Can you help me solve my electrical mystery?

Description : Can you help me solve my electrical mystery?

Last Answer : Any signs of animal life? They can get in the walls and chew on the wires. Or is it the entire area served by that breaker? The breaker could be bad. It happens with anything mechanical.

How to tell if a power strip is burned out?

Description : How to tell if a power strip is burned out?

Last Answer : answer:Personally, I would either toss it, or down grade it to outdoor use only. I wouldn’t take a chance with it in the house. Yes, you can let it cool down, then test it again. But a failure is a failure. Does it have a reset button? What price range did you pay?

I accidently soaked an extension cord. Is it safe to use it again after letting it dry out for awhile?

Description : I accidently soaked an extension cord. Is it safe to use it again after letting it dry out for awhile?

Last Answer : The plug end is easier to dry out than the socket end get out your blow-dryer and set it to high and blow the end that got wet for a while. That will get most of the water off/out of ... up or sputter. Most modern extension cords are pretty watertight so there shouldn't be any water down the wire.

How can a solar array power source be bypassed when the batteries run low?

Description : How can a solar array power source be bypassed when the batteries run low?

Last Answer : Ah got it. If anyone else is interested, you need an “automatic transfer switch” – or get a manual one for that mad scientist charm.

How to stop a signal going through a wire?

Description : How to stop a signal going through a wire?

Last Answer : Use a switch or a variable resistor

Air conditioning will not turn on, is it electrical?

Description : Air conditioning will not turn on, is it electrical?

Last Answer : Pull the Thermostat off the wall and see if it is connected correctly to the AC switch. There should be no dangling wires, and the post labeled for the AC should have an attached wire.