I do not know about any standard tests. Different machine manufaturers do it differently. It also depends if there are insulated bearings (Insocoat etc) or insulated end shields or housings.
Some use an ohmmeter and some use a Megger and test at 500 V. A simple and reliable test is to connect an incandescent lamp from Line to rotor and see if it lights up. If it does, the insulation doesn't work.
BE VERY CAREFUL AND MAKE SURE NO-ONE CAN TOUCH THE ROTOR DURING THE TEST!
The insulation test is done to ensure that there are no paths for leakage current and it is usually not meaningful to take any megohm readings. A simple insulated/not insulated test is OK.
Make sure that all protections, transducer cables, greasing tubes etcetera are in place and functional when you do the test. If you test without these components installed, chances are that you will not notice that they short out an otherwise perfect insulation arrangement. One of the more common problems when "everything was checked" and problems pop up.
Thank you for you reply .
can you tell me the procedures when using the Megger 500 v
Also how to make the insulation test between phase to phase(in details please), i usually do it phase to ground.
Repairing speaking, the Easa´s AR-100 guide specify at least 10 MOhms for IR test done at 500 V. But don´t tell nothing if the Reading is or not temperature corrected, be carefull with this corection. You have more information on the attached file Regards Carlos
