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Help ground

Discussion in 'General Electronics' started by Mateusz Klimczak, Apr 26, 2020.

  1. Mateusz Klimczak

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    Hello, I'm doing grounding for the milling machine and all equipment. Some tools and milling machines are grounded to the socket because they have a pin. But this power supply, which in the photo I got connected so without a pin, there is still an empty space I think to connect a grounding cable there, and whether the cables from the power supply come out to control the motors there is no grounding, I do not know where to connect there, so that the motors and the table have a grounding . I have to somehow ground the vacuum cleaner and the hose which is all made of such plastic without wire. I am asking for help and advice.
     

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  2. Joe Santarsiero

    Joe Santarsiero OB addict
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    I'm no electrician, but I'm pretty sure you should have a 2 conductor plus ground conductor cable attached on the AC side of the supply.

    On the DC side you'll only have a vdc+ and vdc-. There is no ground.

    Static buildup on the vacuum hose can be controlled somewhat by attaching a long piece of uninsulated wire the length of the hose and terminating it to some path that runs to ground. I've found that flexible soldering braid works well for this as long as it's touching the inside and outside of the hose.

    If you want to ground the machine and spindle I think you could run a ground wire from the equipment, but you'll want to use an inline resistor. Unless you're just trying to control static, I don't think you need to ground the equipment if you're using all DC circuits. Electrical guys please correct me if I'm wrong.
     
    Peter Van Der Walt likes this.
  3. Alex Chambers

    Alex Chambers Master
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    Just to add to Joe's comments. You need to be clear about the difference between ground (usually refers to the dc ground of your control circuits) and earth - connected to your mains earth. Connect your vacuum hose to earth using a bare wire as Joe suggested - do not connect it to the ground (DC -) of your control circuitry.
    Alex.
     
  4. Gary Caruso

    Gary Caruso OpenBuilds Volunteer
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    Hi Mateusz,
    For safety you should get a three wire cable/plug (hot-neutral-earth) for that PSU.
    Then the chassis of the PSU will be protected and you wont get shocked if it gets energized (it will trip the breaker).
    After that you can use the chassis of the PSU to run other grounding wires to (technically Earth like Alex said).
    I'm a believer in running earth wire to each motor on the system (which connects to the PSU) to dissipate any static or potential differences on the metal frame of the machine.
    For my career I am a field service engineer working on large medical devises which all follow the same electrical "earthing". I've also worked on commercial flight simulators (electric 100kva systems) and grounding with high strand count wire (2AWG) was very important to dissipate noise from 600V servo controllers.
    If the system is properly earthed you wont need to ground plastic vac hoses.
    Also I wish more people would use shielded cable for power lines such as steppers and routers (with shield drains run to the common earth point).
    Cheers
    Gary
     
    Giarc likes this.

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