584,865 active members*
4,842 visitors online*
Register for free
Login
IndustryArena Forum > Machine Controllers Software and Solutions > Fanuc > Question about AC servo motor type Alpha C
Results 1 to 7 of 7

Hybrid View

  1. #1
    Join Date
    May 2014
    Posts
    174

    Question about AC servo motor type Alpha C

    Hello gentlemen,

    Quick question to the group, I was about to install a new servo amplifier since the old one was faulty, but I wanted to make sure there was no problem witht the motor, so I checked the resistance with the ohmmeter, of all three motors in order to compare since I didn´t hava a nominal value to be used as reference. The motors from axis X and Y read 2.6 ohms in all cable combinations. but the motor from axis Z read 0.08 ohms. To me that reading is close to a short. but I am not a 100% sure, since I don´t know the nominal value.

    Does anyone know what should be the reading for this motor that would like to share please? please see attached picture for motor details. Thank you!




  2. #2
    Join Date
    Apr 2006
    Posts
    111

    Re: Question about AC servo motor type Alpha C

    your motor is short circuit.

  3. #3
    Join Date
    Dec 2003
    Posts
    24216

    Re: Question about AC servo motor type Alpha C

    Is that between all three? UVW ?
    Back feed-rotate it with other means and read the generated voltage between phases.
    Al.
    CNC, Mechatronics Integration and Custom Machine Design

    “Logic will get you from A to B. Imagination will take you everywhere.”
    Albert E.

  4. #4
    Join Date
    Apr 2015
    Posts
    170

    Re: Question about AC servo motor type Alpha C

    Shorted windings on an AC servo usually makes the shaft hard to turn by hand or feel lumpy. Dave

  5. #5
    Join Date
    Dec 2003
    Posts
    24216

    Re: Question about AC servo motor type Alpha C

    I have a Fanuc S5/300 here that is around the same size, it measures 0.75 ohms between winding's.
    Are you sure that is not reading 0.8?
    Al.
    CNC, Mechatronics Integration and Custom Machine Design

    “Logic will get you from A to B. Imagination will take you everywhere.”
    Albert E.

  6. #6
    Join Date
    Aug 2014
    Posts
    232

    Re: Question about AC servo motor type Alpha C

    I had an almost identical motor fail that way, it was full of water. The resistance readings returned to normal once I had dried it out, but it was rusty as hell inside so I swapped it anyway.

  7. #7
    Join Date
    Jul 2017
    Posts
    50

    Re: Question about AC servo motor type Alpha C

    If you have a megger or a multimeter that can check up to 60 Megaohms, check resistance from a phase to ground. A megger is better for this, but a multimeter will detect and obvious problem with insulation leakage.

    From my experience even 20 Megaohms gave me trouble and damaged a servo amp, but luckily for me that was in the cables and the motor windings were still well insulated.

Similar Threads

  1. Fanuc Alpha Servo Motor Test Rig
    By shafts in forum Fanuc
    Replies: 3
    Last Post: 01-11-2016, 01:50 PM
  2. Replies: 0
    Last Post: 05-13-2013, 09:59 AM
  3. Servo Motor Size for Bridgeport type machine
    By native34 in forum Bridgeport / Hardinge Mills
    Replies: 9
    Last Post: 08-26-2009, 08:25 PM
  4. Brush Type Servo Motor Source?
    By Lemo in forum Servo Motors / Drives
    Replies: 2
    Last Post: 06-20-2007, 08:01 PM
  5. Anyone know where to get this exact type of servo motor?
    By SCCoupe in forum DIY CNC Router Table Machines
    Replies: 2
    Last Post: 03-18-2006, 04:58 AM

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •