Pro VFD guys, lets figure out this Yaskawa 626VM3
Close
Login to Your Account
Likes Likes:  0
Results 1 to 6 of 6
  1. #1
    Join Date
    Feb 2014
    Location
    UT
    Posts
    553
    Post Thanks / Like
    Likes (Given)
    4
    Likes (Received)
    102

    Default Pro VFD guys, lets figure out this Yaskawa 626VM3

    Have a machine we bought knowing there was a spindle drive glitch somewhere. Finally got it under power. Before so the drive was cleaned up and visually inspected but not removed. On power up, the drive seemed healthy as it received 3 phase power. However, it seemed on this machine the DC buss does not get charged up until you initiate all the drives and such. As I attempt to do that, I get an F-A00 alarm which appears to be a charging error. When the drive is initially powered, all boards are powered, parameters ar accessible, etc. All seems to work well, but when it tried to initialize, it doesn't like that.

    Now...... I am already onto 'something' as I discovered the morons before had cross threaded L1 into the drive so though the screw was tight, the terminals certainly were not. There was evidence of arcing there but not severe. However, that could have easily thrown things when under load. I am not sure if a Yaskawa will show a diode problem, resistor, etc, or just say "can't do it".....?

    One would think the loss of L1 would immediately get flagged but I have not been able to even get the DC buss charged. I have the screws tight now and was really thinking I found the issue but now wondering what damage that did. The charge light has never lit for me. so I feel confident when the drive tries to charge, something immediately trips and puts her in limp mode.

  2. #2
    Join Date
    Jun 2001
    Location
    St Louis
    Posts
    17,915
    Post Thanks / Like
    Likes (Given)
    1836
    Likes (Received)
    2998

    Default

    Looking on page 211, there ae several possible causes. The simple one is the inrush resistor, If it fails, the bus will not be charged up to the point that the contactor will close to apply full power. The reistor is to avoid having a huge current pulse when the thing is turned on.

    The resistor charges the drive at a low current up to where it is safe to close the contactor. If it is open, the sequence will not occur, and you will have more-or-less the situation you describe.

    If that is nt it, the other choices all seem to involve replacing the inverter, etc.

  3. #3
    Join Date
    Feb 2014
    Location
    UT
    Posts
    553
    Post Thanks / Like
    Likes (Given)
    4
    Likes (Received)
    102

    Default

    Agreed. Finally got the book and talked with Yaskawa and looks like I need to check all components on the DC buss side. There was some indication the MC contactor, or even a capacitor could be at fault but I guess we will know more soon enough. Going to tear into it today.

  4. #4
    Join Date
    Jun 2001
    Location
    St Louis
    Posts
    17,915
    Post Thanks / Like
    Likes (Given)
    1836
    Likes (Received)
    2998

    Default

    A leaky enough capacitor can cause the resistor to fail to charge up the bus..... But normally, that also fails the resistor in short order, because they are only sized for a quick "hit", wattage wise. If the bus is held down by a leaky cap, the resistor gets over-powered and generally opens.

  5. #5
    Join Date
    Feb 2014
    Location
    UT
    Posts
    553
    Post Thanks / Like
    Likes (Given)
    4
    Likes (Received)
    102

    Default

    Well, the meters are pointing me in a different direction and I have the processor board out of it now. There are no line resistors, just a reactor that is built like a Mack truck. The magnetic contactor has a 200V coil in it that is driven by a small relay module that is fired with 24VDC from the processor board. I verified 24V is present at the relay module and waiting for one side to pull down to 0V to fire. In short, the DC buss magnetic contactor is not even trying because the relay module is not getting power from the processor board.

    And the repairs look deep. I have so far traced the 0V line to a tiny SMD transistor, then back to a Schmitt trigger chip.

    At this point, I need to be very sure the drive is fully "enabled" and such but I would not think I would get a "failed to charge" error if the drive was not trying to charge up. When I hit reset, you hear a small mechanical relay on the main board, not sure what it does, but drive looks normal for 4 sec, then that relay kicks out and the error is produced.

    A PCB layout would sure be helpful!

    I guess the drive was sent to Yaswaka some time back to get repaired. They literally did nothing but repair ONLY two little capacitors that had failed. Only another 5-6 on the board! I will probably just change them all if I am ordering parts but no clue where my issue really is just yet.

  6. #6
    Join Date
    Aug 2018
    Country
    INDIA
    Posts
    8
    Post Thanks / Like
    Likes (Given)
    2
    Likes (Received)
    0

    Default

    Quote Originally Posted by huleo View Post
    Well, the meters are pointing me in a different direction and I have the processor board out of it now. There are no line resistors, just a reactor that is built like a Mack truck. The magnetic contactor has a 200V coil in it that is driven by a small relay module that is fired with 24VDC from the processor board. I verified 24V is present at the relay module and waiting for one side to pull down to 0V to fire. In short, the DC buss magnetic contactor is not even trying because the relay module is not getting power from the processor board.

    And the repairs look deep. I have so far traced the 0V line to a tiny SMD transistor, then back to a Schmitt trigger chip.

    At this point, I need to be very sure the drive is fully "enabled" and such but I would not think I would get a "failed to charge" error if the drive was not trying to charge up. When I hit reset, you hear a small mechanical relay on the main board, not sure what it does, but drive looks normal for 4 sec, then that relay kicks out and the error is produced.

    A PCB layout would sure be helpful!

    I guess the drive was sent to Yaswaka some time back to get repaired. They literally did nothing but repair ONLY two little capacitors that had failed. Only another 5-6 on the board! I will probably just change them all if I am ordering parts but no clue where my issue really is just yet.
    Did you solve the issue

    Sent from my Moto G (5) Plus using Tapatalk


Tags for this Thread

Bookmarks

Posting Permissions

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