Need Help! Plasma blows relay..........!!!!WHY


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Thread: Plasma blows relay..........!!!!WHY

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    Default Plasma blows relay..........!!!!WHY

    Hi Guys,

    Me and my dad is building a Milling and Plasma Table.

    The milling Part works fine.

    I am running Mach3. I have connected up the relay as in photo attached but as soon as we turn on our 3 phase plasma cutter the relay blows( I test the relay by removing the signal wire and touching the ground, before the plasma blows it it clicks when touching ground, after it is blown I do the same but only the light goes on. if I power of the 5v and back up it clicks then only).

    It blows the relay and Mach3 says limit switch triggered. (I'm guessing the faulty relay causes that).

    Can you guys please help as this is our only issue left. I hope before the machine is complete.

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    Attached Thumbnails Attached Thumbnails Plasma blows relay..........!!!!WHY-relay-jpg  


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    Community Moderator Al_The_Man's Avatar
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    Default Re: Plasma blows relay..........!!!!WHY

    Is it the contact side that blows?
    If so it is most likely that you are overloading the contact rating or a short circuit/high load develops to blow it.
    What load are you switching?
    Max.

    CNC, Mechatronics Integration and Custom Machine Design

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


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    Default Re: Plasma blows relay..........!!!!WHY

    Is there a way to check what side is bowed? I will have to check the load tommorow. We are using a 3-phase plasma machine



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    Default Re: Plasma blows relay..........!!!!WHY

    You could energize the relay but disconnect the load side, and if you have a meter, see if there is continuity across the output.
    Al.

    CNC, Mechatronics Integration and Custom Machine Design

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


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    Default

    Thanks, I will test. Is my wiring correct as on photo? And is the limit switch triggered error from relay blowing



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    Default Re: Plasma blows relay..........!!!!WHY

    Quote Originally Posted by Al_The_Man View Post
    You could energize the relay but disconnect the load side, and if you have a meter, see if there is continuity across the output.
    Al.
    Load is to much yes, is there a bigger relay we can use on mach3 to activate the plasma



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    Default Re: Plasma blows relay..........!!!!WHY

    Find out the actual load and size a relay accordingly, you may find it hard to find one rated for 5vdc coil.
    If so you could use a 2n7000 Fet and a 12v -24v relay.
    See PDF.
    Al.

    Attached Thumbnails Attached Thumbnails Plasma blows relay..........!!!!WHY-fet2n7000-pdf  
    CNC, Mechatronics Integration and Custom Machine Design

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


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    Default Re: Plasma blows relay..........!!!!WHY

    We spoke to the people where we are purchasing the plasma. they said the relay will be fine. I think it is another issue. I am getting 24v out of all my output ports on mach3.....is this normal? so my signal pin to turn relay on and of has 24v on. I have my V+ (on Mach3 board) running to the V+ on my power supply. Then I have V- (on mach3 board) running GND (where my wall plug runs to on power supply) because there is no V- on the power supply only a COM connection.

    When I connect up my relay with a 5 v power supply I test it by touching the int 1 pin to a GND wire then it opens. Must it not touch a V+ to open?



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    Default Re: Plasma blows relay..........!!!!WHY

    The output from the PC port should be 5vdc maximum, not sure where the 24v would be coming from?
    Unless you have some external wiring mistake!
    Al.

    CNC, Mechatronics Integration and Custom Machine Design

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


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    Default Re: Plasma blows relay..........!!!!WHY

    Yes we have a extra 24v power supply for limit switches and estop



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    Default Re: Plasma blows relay..........!!!!WHY

    This is my wiring diagramPlasma blows relay..........!!!!WHY-wiring-jpgPlasma blows relay..........!!!!WHY-wiring-jpg

    Attached Thumbnails Attached Thumbnails Plasma blows relay..........!!!!WHY-wiring-jpg  


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    Default Re: Plasma blows relay..........!!!!WHY

    That would be 24v supply common, not earth ground.
    There should be a separate earth ground terminal on the input of the P.S. for the service GND.
    Al.

    CNC, Mechatronics Integration and Custom Machine Design

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


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Plasma blows relay..........!!!!WHY

Plasma blows relay..........!!!!WHY