The causes of Low Insulation Resistance of Electrical Equipment and ways to rectify them
Low insulation is approximately always the result of absorption of moisture through the insulated windings, because most of the insulating materials used are hygroscopic (moisture absorbent).
To keep high insulation values, the following care should be taken.
a) Don't permit dust to collect on the motor windings. Dust and dirt absorb and keep moisture, leading to leakage of electricity that may at last result in a breakdown. Clean up the motor windings at regular intervals via blowing compressed air, and wipe the outer surface of windings clean and bright through a dry cloth.
b) Oil and grease are uniformly bad; because they are much harder to remove once they reach the windings and soak them, the result of worn-out bearings, over-oiling, leaky gaskets of oil level indicators, etc. Oil and grease not only create the equipment messy but are good places for dust to settle in. This must be prevented.
c) Guard large motors, rotary convertors, etc. against inclement weather while they are idle, through covering them over with a large tarpaulin and keeping the windings warm through connecting up some electric radiators or infra red lamps all round. Alteration over the working and stand-by sets regularly to preserve both in good condition.
d) Despite all precautions, occasionally motors do get submerged within water. Retrieve them as soon as probable and blow the wet surfaces with compressed air. Dry out through putting them in a hot chamber.
Dampness in windings can be separated by drying out the equipment carefully in a hot chamber or in an impregnating plant, the inside of that is kept at a temperature of 800C to 1000C. The heating should be performed for various hours and in the case of large equipment for one or two days, if needed until all the moisture has been driven out. This can be determined through recording the insulation resistance readings at regular intervals of one or two hours.
Table: Winding insulation resistance at different temperatures
Winding voltage
Megaohms resistance at
200C
300C
400
500C
600C
66 KV and above
1200
600
300
150
75
22 KV to 44 KV
1000
500
250
125
65
6.6 KV to 19KV
800
200
100
50
Below 6.6 KV
25
The insulation resistance should be calculated while motor is hot, when possible. The reason is that though a damp winding will provide a relatively higher reading if taken while cold and so such a reading is not reliable. The reading will be lower while taken 'hot'. Like already stated, the resistance of any insulation falls while the temperature increases that are directly reverse to that of any metallic conductor the resistance of that increases as the temperature increases. While recording insulation resistance of a winding, it is so very significant to note down the temperature of the winding through a thermometer. It is wanted to have a standard technique of recording the readings, say at 750C. All megger readings might after that convert to this common base, through multiplying or dividing them by the suitable conversion factor.
Latest technology based Electrical Engineering Online Tutoring Assistance
Tutors, at the www.tutorsglobe.com, take pledge to provide full satisfaction and assurance in Low Insulation Resistance of Electrical Equipment homework help via online tutoring. Students are getting 100% satisfaction by online tutors across the globe. Here you can get homework help for Low Insulation Resistance of Electrical Equipment, project ideas and tutorials. We provide email based Low Insulation Resistance of Electrical Equipment homework help. You can join us to ask queries 24x7 with live, experienced and qualified online tutors specialized in Low Insulation Resistance of Electrical Equipment. Through Online Tutoring, you would be able to complete your homework or assignments at your home. Tutors at the TutorsGlobe are committed to provide the best quality online tutoring assistance for Electrical Engineering homework help and assignment help services. They use their experience, as they have solved thousands of the Electrical Engineering assignments, which may help you to solve your complex issues of Low Insulation Resistance of Electrical Equipment. TutorsGlobe assure for the best quality compliance to your homework. Compromise with quality is not in our dictionary. If we feel that we are not able to provide the homework help as per the deadline or given instruction by the student, we refund the money of the student without any delay.
metals-transition metals tutorial all along with the key concepts of electronic configuration of 1st transition series metals, physical properties of transition metals, chemical reactivity, variable oxidation states, complex ion formation, alloy
dish antenna is a receiver antenna that receives the signals propagated by the satellite and provide to the t.v. receiver.
Radiation Hazards tutorial all along with the key concepts of Exposure to Radiation, Radiation and Health disorders, Management of Radioactive Waste, Protective measure from Radiation laboratory work and Control of Radiation protection measure
Study of manufacturing process is necessary for installation of any costing system. For Activity Based Costing system as well, it is essential to study the manufacturing process.
The transverse part of the dicot root (Bean) displays the following plan of arrangement of tissues from the periphery to the centre.
Morphology of pteridophytes tutorial all along with the key concepts of Characteristics of Pteridophytes, Life cycle of Pteridophytes, Fossilization Process, Type of fossilization, Types of fossils, Petrifaction, Cast or incrustation, Compression
work, heat and heat capacity tutorial all along with the key concepts of types of process, isothermal process, adiabatic process, isochoric process, isobaric process, reversible and irreversible process
Microscope and Specimen Preparation tutorial all along with the key concepts of The Microscope, Light Microscope, Bright Field Microscope, Dark-Field Microscope, Phase-Contrast Microscope, Fluorescent Microscope, Microscope Resolution and Electron Microscope
Porifera tutorial all along with the key concepts of Characteristics of Porifera, Physical Structure of Porifera, Organic Structure of Porifera, Reproduction of Porifera, Size and Complexity of Porifera
tutorsglobe.com main axis shortened assignment help-homework help by online racemose inflorescence tutors
tutorsglobe.com skin assignment help-homework help by online receptor organs tutors
tutorsglobe.com mono phosphate cleavage assignment help-homework help by online atp as high energy compound tutors
Theory and lecture notes of F distribution and F-test all along with the key concepts of F distribution, Avoiding Left Critical Values, F-Test, Tukey Test, Scheffe' Test, Within Group Variance, One-Way Analysis of Variance. Tutorsglobe offers homework help, assignment help and tutor’s assistance on F distribution and F-test.
Physical systems executing SHM tutorial all along with the key concepts of Simple Pendulum, Compound Pendulum, Torsional Systems, L-C Circuit, Diatomic Molecule-Two-Body Oscillations
Learning-Communication and Social behavior tutorial all along with the key concepts of Habituation, Classical conditioning, Instrumental conditioning, Latent learning and Insight learning
1954412
Questions Asked
3689
Tutors
1476725
Questions Answered
Start Excelling in your courses, Ask an Expert and get answers for your homework and assignments!!