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
Description : A megger is being used to test the insulation of an AC generator. The resistance value of a dry, clean winding will _____________. A. continue to rise as test potential is maintained, ... , becoming fairly steady after 5-7 minutes D. stabilize after approximately 2-4 minutes of fluctuation
Last Answer : Answer: A
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
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
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.
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
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
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
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
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
Description : What is a normal indication on a megger when checking insulation?
Last Answer : Infinity.
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
Description : What is the normal indication on a megger when checking insulation?
Last Answer : infinity
Description : Why is a Megger used for insulation test and not a multi meter?
Last 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
Last Answer : In RE cable the insulation resistance will be above 20 mega ohms.
Description : Name the method used to measure following resistances:- (i) Low resistance (ii) Medium resistance (iii) Insulation resistance (iv) Earth resistance.
Last Answer : Following are the methods used to measure resistances:- (i) Low resistance: 1.Voltmeter-Ammeter Method 2. Kelvin's Double bridge Method (ii) Medium resistance: 1.Voltmeter-Ammeter Method 2. ... of Charge Method (iv) Earth resistance : 1. Fall of Potential Method 2. Earth tester
Description : If the insulation resistance of a cable of length 10 km is 1 mega ohm, its insulation resistance for 50 km length will be
Last Answer : If the insulation resistance of a cable of length 10 km is 1 mega ohm, its insulation resistance for 50 km length will be 0.2 mega ohm
Description : To carry out an insulation resistance test, one terminal of the megohmmeter should be connected to the winding, with the other terminal being connected to the ____________________. A. power supply B. variable resistor C. frame of the machine D. armature
Description : When working on electrical circuits containing large capacitors, in addition to deenergizing the circuit, which of the listed precautions should also be taken? A. Keep all radio equipment ... capacitor insulation resistance. C. Ground the capacitor terminals. D. Check capacitor circuit polarity.
Description : A galvanometer is an instrument used to measure ___________. A. thickness of galvanized metal B. resistance of electrical wiring insulation C. very small amounts of current or voltage D. quantity of galvans in an electric circuit
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
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.
Description : State the methods used to measure insulation resistance and explain Dielectric Absorption method.
Last Answer : There are three types of tests for measuring insulation resistance: 1. Spot test reading or Short Time test 2.Time-resistance test or Dielectric absorption test or Testing methods based on the PI & DAR 3. ... and if value of PI is less than 2 and value of DAR is less than 1.25
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
Description : Megger is used to measure (a) very high resistance or insulation resistance. (b) low resistance. (c) high resistance. (d) very low resistance.
Last Answer : (a)very high resistance or insulation resistance
Description : In a 3-phase extra-high voltage cable, a metallic screen around each core insulation is provided to (a) Facilitate heat dissipation (b) Give mechanical strength (c) Obtain longitudinal electric stress (d) Obtain radial electric stress
Last Answer : In a 3-phase extra-high voltage cable, a metallic screen around each core insulation is provided to Give mechanical strength
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.
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.
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.
Description : The insulation resistance of earth of an installation should be nearly: - a) 0.1 M ohm b) 0.2 M ohm c) 0.5 M ohm d) 1 M ohm.
Last Answer : The insulation resistance of earth of an installation should be nearly: - 1 M ohm.
Description : Why using megger ? how to work megger?
Last Answer : Megger is all about safety. You need to use cables that can meet your demand without putting anyone at risk through earth leakages. So Megger is all about testing cable insulation. You use an insulation tester resistant meter to make sure your cables are standard and properly insulated.
Description : Draw construction of Megger and write operating principle of it.
Last Answer : Megger: Working: Two coils the current coil and pressure coil are mounted at an angle on the same spindle and form the part of the moving system. These coils are connected to a small hand driven ... . When the instrument is not working the pointer may rest at any position on the dial.
Description : Megger is used to test _________. A. Insulation B. Current C. Capacitance D. None of these
Last Answer : Megger is used to test Capacitance.
Description : A megger is basically a/an (a) Moving iron type instrument (b) Moving coil type instrument (c) Hot wire instrument (d) Electrolytic instrument
Last Answer : Moving coil type instrument
Description : Why the input resistance of an ideal OPAMP is infinite and output resistance is zero? secondly, how can we measure these resistances(input and output) in case of an ideal OPAMPand Real OP-AMP in the following conditions when 1- load is not connected. 2- load is connected.
Last Answer : Ans- Ideal OP-AMP is a power ful concept. If one goes through the history of amplifying devices it becomes clear that less it loads the previous stage better the output signal. ie ... . Can refer application notes by device manufacturer available in internet for more precise and practical solutions.
Description : A cylindrical cable of core radius 1.25cm and impregnated paper insulation of thickness 2.13cm and relative permittivity 3.5. Compute the capacitance of the cable/km (in nF
Last Answer : To calculate the capacitance of the cable per kilometer, you can use the following formula: C = ε * ε0 * A / d where: C is the capacitance of the cable per kilometer (in farads) ε is ... * 10^9 = 644 nF/km So the capacitance of the cable per kilometer would be approximately 644 nanofarads.
Last Answer : Cable Insulation Resistance His Of length With Proportional. That is Length Increase If found Insulation Resistance Decreased And Length Decrease If found Increase Gets.
Description : Which of the following statements concerning electrical cables is correct? A. Where they pass through watertight bulkheads, they should be fitted with watertight stuffing boxes. B. Electric cable coverings should ... , or glued in place where nonmetallic insulation is used. D. All of the above.
Description : What is used as insulation for PILC cable?
Last Answer : Impregnated paper.
Description : A cable of core radius 1.25cm and impregnated paper insulation of thickness 2.13cm and relative permittivity 3.5. Compute the capacitance of the cable/km(in nF) a) 195.7 b) 179.5 c) 157.9 d) 197.5
Last Answer : a) 195.7
Description : Is a cable is to be designed for use on 1000 kV, which insulation would you prefer ? (a) Polyvinyle chloride (b) Vulcanised rubber (c) Impregnated paper (d) Compressed SFe gas (e) none of the above
Last Answer : (d) Compressed SFe gas
Description : The insulation of the cable decreases with (a) the increase in length of the insulation (b) the decrease in the length of the insulation (c) either (a) or (b) (d) none of the above
Last Answer : (a) the increase in length of the insulation
Description : The breakdown of insulation of the cable can be avoided economically by the use of (a) inter-sheaths (b) insulating materials with different dielectric constants (c) both (a) and (b) (d) none of the above
Last Answer : (c) both (a) and (b)
Description : In the cables, sheaths are used to (a) prevent the moisture from entering the cable (b) provide enough strength (e) provide proper insulation (d) none of the above
Last Answer : (a) prevent the moisture from entering the cable
Description : If a cable of homogeneous insulation has a maximum stress of 10 kV/mm, then the dielectric strength of insulation should be (a) 5 kV/mm (b) 10 kV/mm (a) 15 kV/mm (d) 30 kV/mm
Last Answer : (b) 10 kV/mm
Description : A certain cable has an insulation of relative permittivity 4. If the insulation is replaced by one of relative permittivity 2, the capacitance of the cable will become (a) one half (6) double (c) four times (d) none of the above
Last Answer : (a) one half
Description : In a cable, the maximum stress under operating conditions is at (a) insulation layer (b) sheath (c) armour (d) conductor surface
Last Answer : (d) conductor surface
Description : What materials are commonly used as cushions between cable insulation and metallic armor?
Last Answer : Jute and Asphalt coverings.
Description : The core of fiber-optic cable is surrounded by ∙ A. wire braid shield ∙ B. Keviar ∙ C. cladding ∙ D. plastic insulation
Last Answer : ∙ C. cladding
Description : The ‘sheath’ is used in cable to (A) provide strength to the cable. (B) provide proper insulation. (C) prevent the moisture from entering the cable. (D) avoid chances of rust on strands.
Last Answer : Ans: A The sheath in underground cable is provided to give mechanical strength.