August 14, 2019 posted by

All electrical installations and equipment comply with insulation resistance specifications so they can operate safely. Whether it involves the connection cables. IR Testing for Low voltage. Circuit voltage, Test voltage, IR Value(Min). Extra Low Voltage, V DC, MΩ. Up to V except for above. These minimum IR testing voltages must always be adhered to in order to accurately measure the Insulation Resistance in all electrical equipment. Any test .

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Usha Aug 31, Value below which Insulation is not acceptable etc.

Measurement of insulation resistance (IR) – Part 2

Please can you help me to know the maximium fire resistance temperture for the follow fire cable with following specifiction: The resistance between Phase-Phase-Neutral-Earth must never be less than 0. Electronic equipment like electronic fluorescent starter switches, touch switches, dimmer switches, power controllers, delay timers could be damaged by the application of the high test voltage should be disconnected. IR Value of Submersible Motor. IR Value for Transformer Ref: Transformer windings are never left floating for insulation resistance measurements.

I wish to thank the author for making this information available to the general public who could be harmed as a consequence. For electric motorwe used a insulation tester to measure the resistance of motor winding with earthing E. Connect the test leads avoid joints.

Treat it as part of the grounded section of the circuit. The wiring and i.rtesting need to test for each other phase to phase with a ground E cable. Please email me to my email.

IR Value at Maintenance Time. Thanks for your article. IR Value for Panel Bus 8. Arunkumar Dec 12, Thoroughly clean i.r.etsting bushings Short circuit the windings. This is happening for both different motors with ideal rating. Avoid meggering when the transformer is under vacuum. Solidly grounded winding must have the ground removed in order to measure the insulation resistance of the winding grounded. At a pressure of V applied between each i.r.etsting conductor and earth for a period of one minute the insulation resistance of HV installations shall be at least 1 Mega ohm or as specified by the Bureau of Indian Standards.


This cause deterioration of the insulation, as well as involving a waste of energy which would increase the running costs of the installation. Motor Name Plate V. The primary source of information is described within IEEE, IEC or national standards which must be reviewed before embarking upon electrical engineering works or projects. What voltage do u use 5 test a v bus bar and what are the expected results.

A meenashankar Jan 07, Virendra Nathe Tiwari Jun 12, The IR tests must be carried out between Phase-Phase-Neutral-Earth with a minimum acceptable value for each test of 0.

Benefits of Permanently Installed Automatic Insulation Resistance (IR) Testing: Part 3 of 3

For any installation, the insulation resistance i.r.testinv shall not be less than: Value for LT to Earth is coming only 43M-ohm, any one can give me solution. Leave a Comment Click here to cancel reply. If this happens, the installation should be subdivided and retested, when each part must meet the minimum requirement.

Sir, it has been observed that during oil replacement procedure of a power transformer in one of our Substations IR values were taken after draining of oil and after filling with oil. Measurement of insulation resistance IR — 2. The example you stated mention some thing in contrary See Below.



Can any one explain the Reason??? He is Presently associate with one of the leading business group as a Deputy Manager at Ahmedabad,India. The transformer Neutral bushing is to be disconnected from earth during the test.

Benefits of Permanently Installed Automatic Insulation Resistance (IR) Testing: Part 1 of 3

If the ground cannot be removed, as in the case of some windings with solidly grounded neutrals, the insulation resistance of the winding cannot be measured. What is the reason? Why to avoid meggering when the transformer is under vacuum?

Auto transformer two windings 1. Ganesh Kumar Aug i.r.gesting, Sami Rashed Dec 29, Three winding transformer 1. A low resistance between phase and neutral conductors, or from live conductors to earth, will result in a leakage current.

Vincenzo Dec 30, Samer Alamouri Jun 30, Insulation resistance tests are commonly measured directly in megohms or may be calculated from measurements of applied voltage and leakage current. Due to the inductive characteristics of transformers, the insulation resistance reading shall not be taken until the test current stabilizes.

I just have doubt that one of the examples of insulation temperature correction factors is given with a probable mistake from the point I looked to the insulator. Value at 60 seconds after application of the test voltage is referred to as the Insulation Resistance of the transformer at the test temperature. If desired, the installation can be tested as a whole, when a value of at least 0. Definitely there will be a temperature rise of 10 degree Celsius from cold to No-load running.