The insulation resistance of earth of an installation should be nearly: - 1 M ohm.
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 : Point out the correct statement. a) JumpIt is an open-source virtual appliance installation and management service b) Converting a virtual appliance from one platform to another is easy proposition c ... vendors support OVF, notably VMware, Microsoft, Oracle, and Citrix d) All of the mentioned
Last Answer : Nearly all major virtualization platform vendors support OVF, notably VMware, Microsoft, Oracle, and Citrix
Description : Insulation Installation?
Last Answer : form_title= Insulation Installation form_header= Install insulation in your home. Does your home currently have insulation?*= () Yes ()No Do you need to remove insulation?*= () Yes ()No What room(s) need insulation?*= _[50]
Description : Fixed capital investment of a chemical plant is the total amount of money needed to supply the necessary plant and manufacturing facilities plus the working capital for operation of the facilities. Which of ... (B) Equipment installation cost (C) Cost for piping (D) Equipment insulation cost
Last Answer : (D) Equipment insulation cost
Description : In a heat treatment shop, steel components are heat-treated in batches of 80 Tons. The heat treatment cycle is as follows; Increase temperature from 30 OC to 850 OC in 3 hours. ... efficiency of 80%, for same requirement. The investment towards installation of the new furnace is Rs. 50
Last Answer : Quantity of steel treated per batch - 80 Tons a. Efficiency of Furnace: Useful heat supplied to steel - 80000 x 0.12 x (850 - 30) = 7872000 kcal/batch .1 mark Total heat ... = Rs. 64400/batch Efficiency of new LPG furnace - 80% Heat supplied in new LPG furnace - 7872000/0.8
Description : Describe with neat circuit diagram the measurement procedure of earth resistance for an installation.
Last Answer : Following procedure (Method) for testing of earth pit resistance with necessary diagrams. 1) Earth Tester : i) Three point method ii) Four point method 2) By Potential drop method 3) Water ... of that earthing pit. In this test the accuracy is less but electrical rods are not required.
Last Answer : Meggar is an instrument which measures the insulation resistance of an electric circuit relative to earth and one another.
Last Answer : The ratio of the resistance of a 100 W, 220 V lamp to that of a 100 W, 110 V lamp will be nearly 4.
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
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
Last Answer : In RE cable the insulation resistance will be above 20 mega ohms.
Description : Consider the following statements: Air vessels are fitted on the suction and delivery sides of a reciprocating pump to 1. Achieve higher speed without separation. 2. Reduce work in overcoming frictional resistance. 3. Avoid excessive vibration ... 2 & 3 only (c) 2, 3 & 4 only (d) 1, 2, 3 & 4
Last Answer : (d) 1, 2, 3 & 4
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
Description : Moisture accumulating in electric motors and generator windings having a cold insulation resistance greater than 50,000 ohms may be baked out with internal heat. This heat can be developed by ____________. ... an electric welder and feeding it into the armature while running the motor at full speed
Last Answer : Answer: A
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
Description : If an alternator is to be inactive for a considerable period of time, which of the following actions should be taken? A. It should be disconnected from the prime mover and raised off its bearing supports ... . D. The windings and collector rings should be protected with a thin coat of grease or oil.
Description : An open in the armature of a DC motor is suspected, but is not found by visual inspection of the commutator. The next step in troubleshooting this problem is to ________________. A. conduct a ... windings C. conduct an insulation resistance test of the armature D. test the commutator for a ground
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
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 insulation failure produces a low resistance current path between two conductors, the resulting condition is known as ____________. A. an open B. a short circuit C. a ground D. a surge
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 : Moisture absorbed in the windings or condensed on the surface of electrical machinery insulation ________. A. is good for long term preserving since most insulation is organic and contains some amount B. ... D. reduces the amount of current supplied or drawn by the machine so horsepower is limited
Description : Which of the instruments listed is used to check insulation resistance? A. Magneto B. Megohmmeter C. Dynamometer D. Rheostat
Description : When a megohmmeter is being used to test insulation resistance, current leakage along the surface of the insulation is indicated by the megohmmeter pointer _____________. A. fluctuating around a ... slightly downscale as voltage is applied D. continually rising as the test voltage is applied
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
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 : The existing resistance of a conductor is dependent upon its length, cross-sectional area, _____________. A. temperature and insulation B. material and insulation C. resistive coefficient and material D. material and temperature
Description : When the current flow through a copper wire increases, its _____________. A. resistance will decrease B. insulation will burn C. temperature will increase D. conductivity will increase
Description : During its operation, loud buzzing and resultant welding of contacts of a magnetic relay may be caused by __________. A. overheating of the contactor coil B. low voltage on the operating coil C. low insulation resistance to ground D. lubrication of the contact bearing points
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 : When a megohmmeter is being used to test insulation resistance, current leakage along the surface of the insulation is indicated by the megohmmeter's pointer _____________. A. dipping toward ... kicking slightly down scale as voltage is applied D. fluctuating around a constant resistance reading
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 : You are testing the insulation in an AC generator with a megohmeter. The resistance value of a dry, clean winding will ____________. A. continue to rise as the test potential is maintained, ... fairly steady after 5 to 7 minutes D. stabilize after approximately 2 to 4 minutes of fluctuation
Description : An insulation resistance reading is taken at 20°C and found to be 10 megohms. What would you expect the resistance reading to be at 40°C? A. 2.5 megohms B. 10 megohms C. 15 megohms D. 20 megohms
Description : When using a megohmmeter to test insulation, good insulation will be indicated by _____________. A. slight kicks of the needle down scale B. a downward dip followed by a gradual climb to the true resistance ... C. a gradual rise in the pointer reading at the outset D. the initial dip of the pointer
Description : When a megohmmeter is used to test insulation, the gradual rise of the pointer reading as a result of continued cranking, is caused by _____________. A. good conductor resistance B. the ... insulation C. the inductive reactance of the windings D. the dielectric-absorption effect of the insulation
Description : Copper is often used as an electrical conductor because it _______________. A. has high resistance at low temperatures B. has a highly polished surface C. is able to pass current with little opposition D. holds insulation together well
Description : On tank vessels with an electrically-driven capstan, the motor should be meggered periodically to test _____________. A. insulation resistance B. eddy currents C. capacitance D. armature reactance
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
Description : An insulation resistance test is performed on a particular piece of electric equipment. In addition to the resistance reading, what information listed below should be entered in the electrical log? A. ... D. The complete nameplate data from the resistance test instrument used to obtain the reading.
Description : What should be the value of insulation resistance of induction motor?
Last Answer : In Rm = kV + 1 M OHMS. Insulation resistance of any electrical machine (motor or generator) should be above 0.5-M ohms in all cases.
Description : What are the points contributes in insulation resistance of the motor?
Last Answer : If the measured insulation resistance of the motor is less than 1 MΩ / kV with a minimum of 1MΩ, when the machine is cold it is to be dried out before full voltage is applied to the terminals of ... voltage. f. Residual charge in the winding. g. Ageing of the insulation. h. Mechanical stresses.
Description : A 10 cm dia steam pipe, carrying steam at 180°C, is covered with an insulation (conductivity = 0.6 W/m.°C). It losses heat to the surroundings at 30°C. Assume a heat transfer co-efficient of 0 ... that of the un-insulated steam pipe (D) Less than the steam pipe with 5 cms insulation
Last Answer : (B) Less than that of the un-insulated steam pipe
Description : The insulation resistance of a DC motor is observed to be 15 MΩ at a temp. of 70°C. what is its value corrected to 40°C. the correction factor for 70°C is 8.0.
Last Answer : Observed resistance at 70°C – 15 MΩ. Temperature correction factor – 8. Rm = kt * Rt kt – correction factor. Rm = 8 * 15 Rt – resistance measured at +°C. Rm = 120 MΩ. Rm – corrected value to 40°C The IR of DC motor corrected to 40°C is 120 MΩ.
Description : Insulation resistance of high voltage circuit breakers is more than (a) 1 mega ohms (b) 10 mega ohms (c) 100 mega ohms (d) 500 mega ohms
Last Answer : (c) 100 mega ohms
Description : Define insulation resistance.
Last Answer : The resistance to current leakage through the insulation.
Description : What instrument is used for measuring the insulation resistance of cables?
Last Answer : Megohmmeter (megger).
Description : Resistance measuring instrument particularly used in determining the insulation resistance
Last Answer : Megger/Megaohmmeter
Description : Insulation resistance is measured by which meter?
Last Answer : megger