Lets Talk Wiring And EMI

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04 Jun 2019 23:20 #135873 by tommylight
Replied by tommylight on topic Lets Talk Wiring And EMI
This should be a sticky!

Also
Position the plasma source as far from the computer and control box as you can.
Do not use cheap keyboard and mouse for plasma machines, find older ones as they tend to have proper shielding. New ones do work, but some new ones will make a lot of trouble, like a lot.
Metal control box, with ground screw on it, all grounds connected to that same screw.
Side info, plasma cutter ground is at a positive level, while the torch is negative.

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05 Jun 2019 00:05 - 05 Jun 2019 00:21 #135885 by rodw
Replied by rodw on topic Lets Talk Wiring And EMI
Well if its to be a sticky, here are some pics.
My star ground is a donated brass relic. I think I'd modify a brass buss bar if I was not donated this. Make sure its ground back for good electrical connection to the table.


This shows ground wires to Z axis stage and floating mount. This is the only place I shared a ground wire as I figured for 50mm, it would be fine and made for a neater install. You can see there is a thick cable bolted between the brass and the table hanging down. This would be your cable to the earth stake if you need it.

In the following photos ground wires are black with a red crimped on lug.



I have not run an earth wire from this to the control box as its secured to the table via several bolts and is there adequately earthed already.

Y axis ground wire one on each motor (yeh, I know Nema 34 is too big Tommy but I upgraded because I found a cool prebuilt 5:1 reduction pinion drive)


Z axis motor ground


So you can see this is not very hard to do.

I use a cheap wireless keyboard and mouse which seems to work reliably but with a 7i76e, I'm only connected via ethernet..
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Last edit: 05 Jun 2019 00:21 by rodw.
The following user(s) said Thank You: tommylight, AgentWD40

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05 Jun 2019 00:08 #135886 by JTknives
Replied by JTknives on topic Lets Talk Wiring And EMI
My controll box looks very similar to that. My main cables from the switches, steppers and encoders are bundled into 2 16 and 1 8 wire cables. And my plasma cutter is sitting about a foot away from my controller. I’m glad I lucked out and don’t have major problems.

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05 Jun 2019 00:18 #135887 by rodw
Replied by rodw on topic Lets Talk Wiring And EMI
I thought something like this might make a good starground point. Throw the ends away and drill out the bolt hole and bolt it to the table via that hole



Cheap as chips
www.jaycar.com.au/16-way-100a-brass-distribution-bar/p/SZ2004
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05 Jun 2019 06:17 #135907 by pl7i92
Replied by pl7i92 on topic Lets Talk Wiring And EMI
the Powersupply Meanwell are very tight
i got real quick in troble with lower then the Width of the meanwell
they interfear

AND EMI
you can get that many EMI on HF fire up torch that the shop power went off

GET the EARTH as low Cable to the GND as posible use the Thickest cable you can LOOK at 10mm²

Mesure all REALY all Metal parts against the EARTH/GND

You can realy get in big trouble if the Naigbour comes with a BILL /Basballbat

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05 Jun 2019 14:25 #135943 by AgentWD40
Replied by AgentWD40 on topic Lets Talk Wiring And EMI
pl7i92,
Do you mean to say that the meanwell power supplies are good, and that cheaper power supplies got you into trouble?

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05 Jun 2019 23:27 #135984 by tommylight
Replied by tommylight on topic Lets Talk Wiring And EMI
@Rod, those connectors I can find here in many, many versions! :)
As for power supplies, I insist on using old laptop power bricks as much as I can, but lately I can not find much of them. They are very good, filtering is good, completely isolated, current limited (this becomes very important when something goes wrong), and firing 2 or 3 of them in series is easy as they are isolated ( be aware that some do have the grounding wired to the negative output terminal, so. It has to be disconnected, simply done by using a power cable with no ground contacts ).
FYI, avoid at all cost power supplies made by "horoz" , they have a picture of a chicken on them! No idea why. They tend to burn to a crisp on their own, burning the filtering coil on the output side. That is magnificently and undeniably done by someone with zero knowledge of electronics. As luck would have it, that was the only manufacturer found here for over a year! Now there are plenty of good ones.

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06 Jun 2019 06:14 #136012 by rodw
Replied by rodw on topic Lets Talk Wiring And EMI
Tommy, I figured the bus bus bars would be easy to find anywhere! Meanwell are well regarded here and is what I use. I did burn a 10 amp one from Stepper onlline but I suspect user error on my part had something to do with that. They did replace it under warranty so one day I will try my hand at another machine.

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06 Jun 2019 23:06 #136124 by tommylight
Replied by tommylight on topic Lets Talk Wiring And EMI
Burned a power supply ????
Was it a switch mode or a transformer/diode rectifier one?
All SMPS ones have short circuit protection and over current protection so they should never burn, except input voltage spikes and material fatigue .
I did test some Chinese 24V 6.5A ones I got lately ( got 5 of them ) and also modified it to have a much wider range of regulation and added an external pot so now it does 17 to 38V, could not push it above as I have a 7805 voltage regulator powering the voltage/amps display and I know it does not handle well 40V, did not want to see the magic smoke! :) . They did endure short circuit for prolonged time, hence me waisting time on the mod.
Did see the magic smoke today though, from an NVIDIA Quadro graphic card that has been in a drawer for the last two years so it gathered some moisture on the dust it had. Was disappointing though, just a miserable puff ! Main board is OK .

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11 Jun 2019 21:26 #136660 by AgentWD40
Replied by AgentWD40 on topic Lets Talk Wiring And EMI
I've got an old mid size pc tower that I'd like to use to house my electronics. The sheet metal that the motherboard mounted to is not ideal for mounting the electronics to. I was thinking I could just mount my electronics to a piece of plexiglass, then mount the plexi to the motherboard's mounting holes.

Anyone see any problems with this plan?

Finally, the case is riddled with holes where various things were mounted, eg LEDs, disc drives, etc. Would it be advisable for me to cover up all these openings with some kind of metal for shielding (except for some ventilation) or is it probably not necessary ?

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