Re: Meggar readings
Megger, and how to use and interpret the readings.
I have always dealt with the Biddle Megger Company and now the Company name is AVO.
The person that I deal with when I have a question is, Jeff Jowett of the AVO Company. Jeff is a Applications Engineer with the AVO company.
{Moderator's Note: Edited to remove Jeff's personal contact information. If you wish to contact Jeff, please send a Private Message to friebel, and ask for the contact phone numbers and email address.}
If you contact Jeff, I know that he will send you two booklets. One is called "A Stitch in Time", it is a Complete Guide to Electrical Insulation Testing Featuring Megger Insulation Testers.
The other booklet is "Getting Down To Earth". Believe me, if you read and understand all of the information that is in the two books, you will be well prepared to handle any situation with Megger Testing.
Now to answer the question about what is an acceptable reading. Naturally, Infinity would be the best and ultimate reading that you would like to see, but what is the acceptable low reading.
In some of the previous threads the "One-Megohm-Reading" was mentioned.
Let me give you an example, if you had a 2300-volt motor, and you were testing the motor windings with a 1000 volt megger, the minimum reading that would be acceptable would be 2.3 Megohms. That is where this "One Megohm per 1000 volts" comes in.
If you were checking a 460 volt motor, you would use the 1000 volt scale, and the minimum reading that is acceptable is One-Meg-Ohm.
But, when your reading is down this low, it is time for you to start thinking about changing the motor and putting a motor in that will be reading Infinity.
[ June 09, 2005, 10:10 AM: Message edited by: charlie b ]