Dangers of Working with Inverters?
Close
Login to Your Account
Results 1 to 13 of 13
  1. #1
    Join Date
    Jan 2019
    Country
    UNITED STATES
    State/Province
    Rhode Island
    Posts
    18
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    0

    Question Dangers of Working with Inverters?

    Hey All,
    I have a 1992 Fadal VMC40 with the mitsubishi Freqrol Z300 Model Z320-7.5k-UL. I often get a spindle fault upon starting the machine, but when I let it warm up and sit for half an hour or so it works no problem. I figured it was the inverted because I was getting an alarm on it and would have to reset.

    Today, the inverter just started smoking.

    I assume I'll have to replace it, but I'd like to take a look and see if there's something obvious that I or someone substantially more qualified could repair.

    My question is this: What are the dangers of working on inverters that have previously been under power? I'll identify the capacitors and discharge them. Is that the only risk? Anyone have experience with these inverters in particular? Or have an idea of what might be going wrong?

    Thanks as always.

  2. #2
    Join Date
    Jul 2009
    Location
    Peoria, IL
    Posts
    11,637
    Post Thanks / Like
    Likes (Given)
    50
    Likes (Received)
    8879

    Default

    Once the caps are discharged, it's pretty safe. Sounds like an IGBT module has shorted.

  3. Likes lumley32 liked this post
  4. #3
    Join Date
    Jan 2019
    Country
    UNITED STATES
    State/Province
    Rhode Island
    Posts
    18
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    0

    Unhappy

    Well, uh, I think I found the problem. The silver (aluminum) unit that mounts to the heat sink has...melted. Is this the IGBT module? Further input and advice always appreciated.

    inverter-pic.jpg

  5. #4
    Join Date
    Sep 2002
    Location
    People's Republic
    Posts
    2,605
    Post Thanks / Like
    Likes (Given)
    190
    Likes (Received)
    1912

    Default

    Nah, they all look like that.......

    kidding..........


    pull the numbers off it and google it, some are discontinued, but there are guys who specialize in finding that type stuff

  6. #5
    Join Date
    Jan 2019
    Country
    UNITED STATES
    State/Province
    Rhode Island
    Posts
    18
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    0

    Default

    Looks like it's the brake resistor. Is this a regen circuit issue? I have no idea what I'm doing...

    brake-resistor-manual.jpg

  7. #6
    Join Date
    Oct 2012
    Location
    Pennsylvania
    Posts
    300
    Post Thanks / Like
    Likes (Given)
    119
    Likes (Received)
    137

    Default

    Quote Originally Posted by nineandtwothirds View Post
    Looks like it's the brake resistor. Is this a regen circuit issue? I have no idea what I'm doing...

    brake-resistor-manual.jpg
    Based on your pic, it's probably the brake resistor. You could try replacing that by itself, but something else in the drive may have went that caused the resistor to go.

    You may be able to disconnect it and try the drive. It may fault if it doesn't sense it. If that's the case, you should be able to change a parameter in the drive to disable the braking - unless it's controlled by the CNC.

    OR - a quick ebay search turned up a few of that model for $300 or so. It may be better to buy another unit than to put money into one that's already been smoked and overheated.

  8. #7
    Join Date
    Jul 2008
    Country
    UNITED STATES
    State/Province
    South Carolina
    Posts
    587
    Post Thanks / Like
    Likes (Given)
    183
    Likes (Received)
    333

    Default

    "Today, the inverter just started smoking."

    You realize gum and patches are available....

  9. Likes 4GSR, Rudd liked this post
  10. #8
    Join Date
    Jul 2009
    Location
    Peoria, IL
    Posts
    11,637
    Post Thanks / Like
    Likes (Given)
    50
    Likes (Received)
    8879

    Default

    Pretty common failure mode. The braking IGBT has likely shorted and dumped the DC bus voltage into the braking resistor continuously until something finally let go. This is so common that many machines have a thermistor on the braking resistor to shut down if the resistor gets too hot.

    Check all of the transistor modules. I think you will find one has a dead short.

  11. Likes Hightemp, motion guru, JST liked this post
  12. #9
    Join Date
    Sep 2002
    Location
    People's Republic
    Posts
    2,605
    Post Thanks / Like
    Likes (Given)
    190
    Likes (Received)
    1912

    Default

    Quote Originally Posted by Hodge View Post
    "Today, the inverter just started smoking."

    You realize gum and patches are available....
    Look, if you are going to post something, try to be useful

    Like, tell the guy what kind of gum you are suggesting, I mean, is it juicy fruit, sugarless

    People need to know

  13. Likes Hodge, tdmidget liked this post
  14. #10
    Join Date
    Oct 2010
    Location
    Dewees Texas
    Posts
    2,212
    Post Thanks / Like
    Likes (Given)
    26
    Likes (Received)
    579

    Default

    One thing to check is your incoming voltage. One of my invertor's braking resistor will get so hot you could fry eggs on it when the voltage gets over 248. 245 is OK, so a buck boost transformer dropped it to 236 as the power company was unwilling to adjust it this time.

  15. #11
    Join Date
    Jan 2006
    Location
    Angier, North Carolina
    Posts
    2,513
    Post Thanks / Like
    Likes (Given)
    992
    Likes (Received)
    886

    Default

    Quote Originally Posted by nineandtwothirds View Post
    Well, uh, I think I found the problem. The silver (aluminum) unit that mounts to the heat sink has...melted. Is this the IGBT module? Further input and advice always appreciated.

    inverter-pic.jpg
    Not now, it isn't!


  16. #12
    Join Date
    Jul 2008
    Country
    UNITED STATES
    State/Province
    South Carolina
    Posts
    587
    Post Thanks / Like
    Likes (Given)
    183
    Likes (Received)
    333

    Default

    Quote Originally Posted by gustafson View Post
    Look, if you are going to post something, try to be useful

    Like, tell the guy what kind of gum you are suggesting, I mean, is it juicy fruit, sugarless

    People need to know
    My pardon, nicotine gum, of course

  17. Likes gustafson liked this post
  18. #13
    Join Date
    Sep 2011
    Country
    UNITED STATES
    State/Province
    Virginia
    Posts
    24,675
    Post Thanks / Like
    Likes (Given)
    7561
    Likes (Received)
    7714

    Default

    Quote Originally Posted by awake View Post
    Not now, it isn't!

    And this is why the nation has so much college debt?

    Usta bee we'd have just said:

    "Not no more, it ain't"

    ... and had money left for beer.


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
  •