Page 1 of 2 12 LastLast
Results 1 to 15 of 17
  1. #1
    Join Date
    Aug 2019
    Location
    Revesby - Sydney Australia
    Age
    56
    Posts
    1,183

    Default Source for 3phase machine switch box?

    Does anyone know of good contactor based machine power switches?

    I'm thinking of a little box with a big emergency stop button on the front,
    and a power latched relay inside for safety after power outages et c.


    Searches for 3 phase starter box show plenty of the traditional type
    (small red and green buttons on a huge case),
    but I haven't found anything I would like to put on a table saw, for example.

  2. #2
    BobL is offline Member: Blue and white apron brigade
    Join Date
    Feb 2006
    Location
    Perth
    Posts
    7,182

    Default

    Do you need the contactor switch as well?

    If so, you wont need a power latched relay inside for safety after power outages etc as most contactors already have this built in.

    Unless you can find second hand then be prepared to shell out $$$ for a decent one.
    In some cases it's getting like you might as well buy a VFD for similar money and get all the extra benefits.

    If you want a big red off switch you can wire that into a the VFD low V control circuit.
    An extra big switch can be obtained if a Large Paddle type switch is used.
    Plenty of samples on ebay.

  3. #3
    Join Date
    Aug 2019
    Location
    Revesby - Sydney Australia
    Age
    56
    Posts
    1,183

    Default

    Good point Bob - the Contactor IS the "power latched relay."



    I have seen those paddle type things, but they look too flimsy to me. Something like this:
    https://www.cef.co.uk/catalogue/prod...ion-metal-clad
    looks a bit better (but that is just single phase? 2 switches)



    For my Hercus lathe, I built a metal box with a metal emergency switch:
    IMG_0007.jpg


    Can always make something similar, but was hoping to not re-invent the wheel if something good already existed

  4. #4
    BobL is offline Member: Blue and white apron brigade
    Join Date
    Feb 2006
    Location
    Perth
    Posts
    7,182

    Default

    Quote Originally Posted by nigelpearson View Post
    Good point Bob - the Contactor IS the "power latched relay."
    I have seen those paddle type things, but they look too flimsy to me. Something like this:
    https://www.cef.co.uk/catalogue/prod...ion-metal-clad
    looks a bit better (but that is just single phase? 2 switches)
    The electromagnetic switch on most contactors usually runs on just one phase so all you need is a simple switch.

  5. #5
    Join Date
    Apr 2018
    Location
    Perth
    Posts
    168

    Default

    Quote Originally Posted by nigelpearson View Post
    Good point Bob - the Contactor IS the "power latched relay."



    I have seen those paddle type things, but they look too flimsy to me. Something like this:
    https://www.cef.co.uk/catalogue/prod...ion-metal-clad
    looks a bit better (but that is just single phase? 2 switches)



    For my Hercus lathe, I built a metal box with a metal emergency switch:
    IMG_0007.jpg


    Can always make something similar, but was hoping to not re-invent the wheel if something good already existed
    Thats simply a estop actuator with 3 contact blocks. A electromagnetic switch is designed so if power is supplied it requires a physical action to operate the switch and switch power. The estop you show , if released ( assuming NC contacts) the the power will be switched on. Only option is a small 3 phase starter. Can be wired with a remote stop start station with a mushroom head stop if needed so contactor box isnt in way of anything.

    Diagram shows 24vdc power supply but easier option is 24vac power supply for retic controller and fit 24vac coil to contactor. That way parts are easy to get.

    Full-voltage-non-reversing-3-phase-motors.jpg

  6. #6
    Join Date
    Aug 2019
    Location
    Revesby - Sydney Australia
    Age
    56
    Posts
    1,183

    Default

    Quote Originally Posted by Sparksy View Post
    Thats simply a estop actuator with 3 contact blocks

    Indeed. Picture was illustrating a solid metal box, and a switch which will last when I bash it with my fist or a hammer
    (unlike most small power switches I have seen).


    More complicated motor control boxes (e.g. anything with a motor reverse, or a coolant pump) do seem to use 24V control, but that means an extra transformer or power supply in the box. Which means my simple little box now has 4 things in it; contactor, tranny, start button, stop button (and maybe a DIN rail to hold the contactor, and a terminal block).




    P.S. for a small machine like that lathe, I don't mind if it accidentally turns on when someone plugs the 3phase plug in, but for a 12" circular saw blade, I wanted a bit more safety.

  7. #7
    Join Date
    Apr 2018
    Location
    Perth
    Posts
    168

    Default

    Quote Originally Posted by nigelpearson View Post
    Indeed. Picture was illustrating a solid metal box, and a switch which will last when I bash it with my fist or a hammer
    (unlike most small power switches I have seen).


    More complicated motor control boxes (e.g. anything with a motor reverse, or a coolant pump) do seem to use 24V control, but that means an extra transformer or power supply in the box. Which means my simple little box now has 4 things in it; contactor, tranny, start button, stop button (and maybe a DIN rail to hold the contactor, and a terminal block).




    P.S. for a small machine like that lathe, I don't mind if it accidentally turns on when someone plugs the 3phase plug in, but for a 12" circular saw blade, I wanted a bit more safety.
    Buy a 3 phase magnetic motor starter with a 240vac coil. Dont worry about the buttons on the front of it except for the red which will work as the overload reset . then buy a stop start station to mount on front of machine. Wire up as per this diagram. Easy enough but should really get a sparky to do it , depends on state regs. You could also just buy the contactor and overload and fit into a small enclosure which may be cheaper, with the motor starter you will need to remove some of existing connections.

    stop start.jpg stop start with neutral.jpg

  8. #8
    Join Date
    Jul 2011
    Location
    Berowra Waters
    Posts
    149

    Default

    I’ve never seen a hammer proof emergency stop switch, not saying they’re not made, but I’ve never seen one.

  9. #9
    Join Date
    Apr 2018
    Location
    Perth
    Posts
    168

    Default

    Quote Originally Posted by riverbuilder View Post
    I’ve never seen a hammer proof emergency stop switch, not saying they’re not made, but I’ve never seen one.
    Thats why I used to install large Estop buttons like this one. At least they only hit it once.
    e-stop.jpg

  10. #10
    Join Date
    Nov 2011
    Location
    Port Sephens NSW Southside
    Posts
    123

    Default

    Nigel
    What's in your switch box at the moment, I believe your lathe is Hercus (9 inch or 260) & running on 3ph. Any chance of a picture of the inside. If you want a larger eStop, you should only have too put the new switch in series with the existing STOP button, as this interrupts the hold cct on the contactor.

    Do you have a wiring diagram for it? I have copies of the original Hercus ones

    JohnQ
    Last edited by JohnQ; 2nd Aug 2021 at 07:42 PM. Reason: spelling

  11. #11
    Join Date
    Aug 2019
    Location
    Revesby - Sydney Australia
    Age
    56
    Posts
    1,183

    Default

    Hi John.

    Hercus: Yes, 3 phase. Switch box is just a simple on/off, but I'm using a triple gang emergency stop switch instead of the usual seperate on/off:
    IMG_0008.jpg


    Table saw (Tanner): No switch box. Motor is just attached to a plug, just like these other old ones a Google image search found for me:
    259815636.jpgblog4930119a100f96c51f1ff518c5bcea54.jpg


    The Hercus can stay as it is - a simple "unsafe" power switch suits a simple machine -
    unless I foolishly add extra functionality/circuitry (RPM meter, electronic lead screw?).

    The table saw is the issue. For now I will just put a clipsal 56 series switch on it,
    until I find a good little contactor based box?

  12. #12
    Join Date
    Nov 2011
    Location
    Port Sephens NSW Southside
    Posts
    123

    Default

    Nigel
    Sorry, should have read all of the last line

    "but I haven't found anything I would like to put on a table saw, for example"

    JohnQ

  13. #13
    Join Date
    Dec 2007
    Location
    Sydney
    Posts
    395

    Default

    Nigel I have a few solid 3 phase old stop buttons in the stash. Foot or knee style.
    Dont want to go out in the cold atm to take photos as my left shoulder is throwing a spas
    Happy to do it tomorrow if you’re interested.
    H.
    Jimcracks for the rich and/or wealthy. (aka GKB '88)

  14. #14
    Join Date
    Aug 2019
    Location
    Revesby - Sydney Australia
    Age
    56
    Posts
    1,183

    Default

    Thanks Henry. Take your time

  15. #15
    Join Date
    Dec 2007
    Location
    Sydney
    Posts
    395

    Default

    Here’s a few.
    All except the plastic red with the P on it are self contained boxes, that is a surface mount?
    Most appear to lock in when pushed.
    A few are all cast iron you probably could hit them with a hammer
    When this latest covid f u is finished your welcolme to come over and grab what you need.
    H.
    Attached Images Attached Images
    Last edited by clear out; 6th Aug 2021 at 12:00 AM. Reason: Adding photo
    Jimcracks for the rich and/or wealthy. (aka GKB '88)

Page 1 of 2 12 LastLast

Similar Threads

  1. shaoxing machine tools cq6230 lathe spindle switch
    By Govy in forum METALWORK GENERAL
    Replies: 8
    Last Post: 21st Mar 2020, 10:18 PM
  2. Milling Machine broken switch replacement where to buy ?
    By topari in forum METALWORK GENERAL
    Replies: 19
    Last Post: 20th Dec 2016, 09:15 PM
  3. Switch Enclosure- Switch Position Identification.
    By Anorak Bob in forum METALWORK GENERAL
    Replies: 17
    Last Post: 19th Jul 2016, 11:00 AM
  4. 3phase v 1phase tig?
    By DoctorWu in forum WELDING
    Replies: 2
    Last Post: 28th Sep 2009, 08:20 AM

Posting Permissions

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