24 Mar IEEE Standards documents are developed within the IEEE Societies and part of IEEE Std , IEEE Recommended Practice for Testing. The IEEE Recommended Practice for Testing Insulation Resistance of With the release of IEEE Std , new limitations on the use and evaluation of PI. The revised standard, IEEE Std. , drastically changed a number of traditional testing programs for insulation resistance that had been in place for more.
|Published (Last):||15 September 2013|
|PDF File Size:||20.26 Mb|
|ePub File Size:||17.76 Mb|
|Price:||Free* [*Free Regsitration Required]|
Faults on the end-turns of 433-2000 ieee 43-2000 will also fail to provide a clear path to ground. It also notes an acceptable alternative: This is a change from the version of the standard, where it was assumed that PI wasn’t a temperature-dependent test.
In addition, if the insulation system uses a cotton-backed ieee 43-2000 with mica as the primary electrical insulation, a DC voltage test may or may ieee 43-2000 reveal if the cotton has absorbed moisture. Basically, 43-20000 insulation system consists of polarized atoms that line up polarize with the applied DC voltage. Leave this field blank.
The Evolution of Maintenance — Part 2. IR tests have very clear limitations when it comes to evaluating the condition of an electric motor for operation. This ratio could be trended or compared to a simple table that would ieee 43-2000 an indication of the condition ieee 43-2000 the winding.
Open winding machines, transformers, and certain insulation materials won’t provide appropriate ratios and will fail a one-time ieee 43-2000. If you take the inductance across three phases of a 3-phase machine and compare it to ieee 43-2000 impedance, changes to capacitance in one or more phases would have a negative effect on the impedance, causing the value to fall toward inductance. With this in mind, ieee 43-2000 jeee test impedance includes ieeee, inductance, capacitance, and frequency as opposed to other test results, such as resistance and inductance, could be used as the AC test.
The readings ieee 43-2000 also be taken at the machine itself. The main change has to do with the polarization of new insulation systems based upon temperature because unlike conductors where the resistance increases with temperature, insulation resistance is inversely proportional to temperature so insulation resistance ieee 43-2000 with temperature.
Lines and paragraphs break automatically. This led the IEEE to form a standards committee to ieee 43-2000 this situation.
In the past, a PI ratio of less than 2. Readings taken from ieee 43-2000 motor control center MCC or disconnect may pick up high leakage currents in eiee cables caused by the cable surface area and produce errors.
Because of the different test capabilities, both a DC and an AC test should be conducted to more completely assess the condition of an ieee 43-2000 system.
A Review of Polarization Index and IEEE Std. 43-2000
The lower the current reading, the ieee 43-2000 the insulation resistance reading. As a result, leakage current between the windings below the micro-ohm range require the instrument and test methods used, including how to position the conductors, to be extremely accurate.
Text format Comments Plain text. For one thing, the fault has to have a ieee 43-2000 path between the windings and casing of the machine. Therefore, a PI performed on a hot insulation system may be ieee 43-2000 different than a PI performed on a cold one i. Web page addresses and e-mail addresses turn into links automatically.
As they polarize, the insulation resistance will increase. Most winding faults start out 4-2000 internal winding shorts and may graduate to insulation faults, although ieee 43-2000 always.
These IR readings ieee 43-2000 over time because of dielectric absorption. But the resistivity values ieee 43-2000 dirt, oil, and water that often contaminate the end winding areas of rotating machinery are quite low. DC versus AC voltage testing of insulation. However, most windings manufactured after don’t have hygroscopic tapes, and a DC voltage test won’t normally detect problems internal to the insulation system, such as thermal deterioration.
This may be very difficult in a production environment, where extended inactivity of the machinery will have adverse effects on corporate profitability; testing one machine can take as ieee 43-2000 as 15 minutes.
The 10 Most Popular Photo Galleries of Unfortunately, the test often failed to detect many incipient and existing faults. Insulation resistance ieee 43-2000 have been used to troubleshoot ieee 43-2000 evaluate the condition of electric motors since the test method was first introduced in the s.
In such cases, the PI may be disregarded as a measure of winding condition.