Posting a message to the forum will remove the above advertisement

Discuss 3-Phase Motor Testing in the Industrial Electrician Talk area at ElectrciansForums.co.uk.

Please make sure you checkout our forum sponsors, many do discounts for members and, they keep the forum free to use.
  1. Darrensparky
    Offline

    Darrensparky New EF Member

    Location:
    Essex
    Hi I'm Darren and I work as a apprentice for a manufacturing company.

    I was testing a 3kw 3-phase motor as it blew a fuse and when doing my IR test down to earth I got a reading of around 11Gohms. I was under the impression that the reading had to be above 1Mohm which this is as far as I am aware but I was advised by my colleague that this is a bad reading and the motor is no good. Can someone confirm for me if I am right or wrong and why :)


    Thanks
     
  2. telectrix
    Offline

    telectrix Scouser and Proud of It Trusted Advisor

    Location:
    cheshire/staffordshire
    Business Name:
    Telectrix
    that is an extremely high reading. as 1 Gig is 1000 Meg. most IR testers won't read that high. if it blew a fuse, i'd be inclined to IR measure between each winding and also a resistance test of each winding. if good, then fire it up with new fuse and measure currents.
     
    • Like Like x 1
  3. LeeH
    Offline

    LeeH Insert witty monkey comment here. Electrician's Arms

    Location:
    Lincs
    As tel said, you have you ohms mixed up somehow.

    Test all phases to ground again and between them @500v. Then check all the windings are balanced (the same).

    Does the motor run freely?
    Clamp on your ammeter and see what the FLC is.
     
    • Like Like x 1
  4. Pete999
    Offline

    Pete999 Trusted Advisor

    Top Poster Of Month

    Location:
    Northampton
    What the last two said, Tel and LeeH
     
  5. telectrix
    Offline

    telectrix Scouser and Proud of It Trusted Advisor

    Location:
    cheshire/staffordshire
    Business Name:
    Telectrix
    or it could just be a tired fuse.
     
    • Like Like x 1
  6. Marvo
    Offline

    Marvo GMES....You absolute beauty. YOU ROCK DUDE!!!! Staff Member

    Location:
    South Africa
    I usually take a hammer to the blown fuse and post mortem it to see if it went with a proper bang or whether it was just a lazy blow.

    11Gohms is an enormously high IR reading, not sure why your colleague would be unhappy with it......
     
    • Like Like x 1
    • Agree Agree x 1
  7. HandySparks
    Offline

    HandySparks Trusted Advisor

    Location:
    Hampshire
    Business Name:
    Neish Electrical Services
    Cracking turn of phrase. I'll have to use it sometime.
     
    • Like Like x 3
  8. LeeH
    Offline

    LeeH Insert witty monkey comment here. Electrician's Arms

    Location:
    Lincs
    Yeah, lazy blows are no good. I like a little vigour.
     
    • Like Like x 2
  9. Marvo
    Offline

    Marvo GMES....You absolute beauty. YOU ROCK DUDE!!!! Staff Member

    Location:
    South Africa
    Yeah, some things lose (or gain) a little in translation :)
    Could have probably phrased that better.
     
    • Like Like x 1
  10. LeeH
    Offline

    LeeH Insert witty monkey comment here. Electrician's Arms

    Location:
    Lincs
    IR of a motor to blow jobs in 6 posts.

    Awesome.
     
    • Funny Funny x 1
Loading...
Similar Threads - Phase Motor Testing Forum Date
3 phase motor over current formula Electrical Forum Sep 5, 2017
NVQ3 2356, three phase question Electrical Courses & Electrical NVQ's Today at 6:40 PM

Share This Page

  • Electricians Directory Post a Domestic Job Post a Commercial Job