How do you pass shielded servo motor cables through the cabinet wall/panel?

arvidb
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03 Aug 2022 00:10 #248884 by arvidb

How do you pass shielded servo motor cables through the cabinet wall/panel? was created by arvidb

How do you pass shielded servo motor cables through the cabinet wall/panel?

In an ideal world there would be a connector that:

* Is rated for at least 250 VAC and with a choice of different sizes/current ratings
* Has 4-pin female panel connector and male cable connector
* Doesn't require soldering (since not recommended for mains voltage)
* Doesn't require €1000 in tools for crimping, inserting, and extracting pins
* Clamps the shield braid all around (no pigtail connection of shield)
* For the panel connector: securely connects the shield to the panel

I guess as hobbyists we are out of luck? So how do you do this? Pass cables through without connectors, perhaps without connecting the shield to the cabinet? Soldered connectors and no shield? Or did you invest in a crimping tool? Some other more clever solution?

It would be great to see pictures too.

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arvidb
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03 Aug 2022 05:11 #248899 by arvidb

Replied by arvidb on topic How do you pass shielded servo motor cables through the cabinet wall/panel?

Maybe using EMC glands is a good idea? I did find some reasonably priced ones: LAPP SKINTOP MS-SC-M + nut - although the glands are out of stock.

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tommylight
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03 Aug 2022 07:49 #248908 by tommylight

Replied by tommylight on topic How do you pass shielded servo motor cables through the cabinet wall/panel?

Drill a bigger hole?
That is what i usually do, or sometimes re-route the cables if they are long enough, do not cause issues, no risk of interference, etc.

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arvidb
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03 Aug 2022 08:49 #248909 by arvidb

Replied by arvidb on topic How do you pass shielded servo motor cables through the cabinet wall/panel?

So you thread the cable through with the connector(s) still on and leave them loose? No strain relief or shield connection?

Curious, how does re-routing help?

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rodw
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03 Aug 2022 10:04 #248913 by rodw

Replied by rodw on topic How do you pass shielded servo motor cables through the cabinet wall/panel?

I feel your pain and want to find a solution too. On a little mill I retrofitted, I justpassed them through a cable gland that worked pretty well.
Then the next enclosure I went back to GX16 connectors but the soldering really got to me so I paid a mate who had been trained in soldering to NASA standards to do it. He did not enjoy it either.

Andy suggested the neutrik powercon connectors www.neutrik.com/en/products/power but I still see that awful word solder!

At the motor end, I have been using automotive QC connectors. These do require crimping but I was able to use a crimper I bought for about $40 from Amazon for JST connectors.

I like these because they are nice and light so OK suspended in the air. Note they are not compatible with the more familiar red/blue/yellow automotove crimp terminals (which I also use for some applications

Any Ideas, please let me know... Lets get rid of soldering!

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tommylight
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03 Aug 2022 10:35 #248916 by tommylight

Replied by tommylight on topic How do you pass shielded servo motor cables through the cabinet wall/panel?

arvidb wrote:
So you thread the cable through with the connector(s) still on and leave them loose? No strain relief or shield connection?

Curious, how does re-routing help?

I just put those plastic/pvc round thingies to protect wires from scratching.

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andypugh
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03 Aug 2022 12:35 #248925 by andypugh

Replied by andypugh on topic How do you pass shielded servo motor cables through the cabinet wall/panel?

arvidb wrote:
How do you pass shielded servo motor cables through the cabinet wall/panel?

You mention "shielded" so my favoured Neutrik (SpeakCON and PowerCON) won't work.

I use Lemo quite a bit, though I tend to scavenge them or buy used from eBay.

M23 are good, but expensive. Mouser seem most reasonable:
www.mouser.co.uk/ProductDetail/Amphenol-...%252BmAEXCHfDw%3D%3D
Bear in mind that often you have to buy shell, backshell, insert ans terminals separetely. That's a kit.

I used M23 to pass the power and feedback for the 4th axis through the mill to allow it to be disconnected.

I swapped the unobtainable connectors on a servo motor for SpeakCON and salvaged Lemo:
Before: photos.app.goo.gl/HqjLvfHWQpqkuHzg8
After: photos.app.goo.gl/s8ecWDui7QaZDpJj8
Then after buying a bigger Lemo from ebay: photos.app.goo.gl/P5sz9dqDLwavKatG7

The solder Lemos are vacuum-tight. Crimp ones are not, and the crimping tools are very expensive. However I have found that this style tool (I have two sizes now) work for D-sub, Lemo and M23: www.amazon.co.uk/Laser-7533-Indent-Crimping-Tool/dp/B07NDVC3VS

And, that mention of D-sub brings me to the real point of this reply. Ordinary D-sub have a higher current and voltage rating than you might guess:
docs.rs-online.com/869a/A700000007669880.pdf
750V and 5A, and it's not a fancy one.

But, you might want to look at the actual fancy ones, with mixed terminals so that you can run signal and power (40A) high voltage (2800V), pneumatic, optical or coax through the same connector:
uk.rs-online.com/web/c/connectors/usb-d-...imensions=4292006345

Drop-down the "contact type" option here to see the supported contact types: uk.rs-online.com/web/c/connectors/usb-d-...tors/d-sub-contacts/

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Todd Zuercher
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03 Aug 2022 16:24 #248947 by Todd Zuercher

Replied by Todd Zuercher on topic How do you pass shielded servo motor cables through the cabinet wall/panel?

Andy, the servo motor connectors you replaced in the above photos look like the mil spec Amphenol type connectors that seem to be common on servo motors. They are generally available, but come in a myriad of options and configurations that can be difficult to discern exactly what you have to match with. (They are also often a bit pricey but very high quality.)

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arvidb
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03 Aug 2022 22:39 #248980 by arvidb

Replied by arvidb on topic How do you pass shielded servo motor cables through the cabinet wall/panel?

rodw wrote:
I feel your pain and want to find a solution too. On a little mill I retrofitted, I justpassed them through a cable gland that worked pretty well.

Yeah, passing them through a cable gland sounds more and more like a good solution.

While soldering connectors is a PITA that's not the main reason I want to avoid soldering: with the contacts carrying hundreds of volts and multiple amps, any bad connection will cause heating, which could make the solder melt and release the cable. At these voltages you really want a physical connection of the cable that is unaffected by heat.

Those automotive QC connectors look interesting. As long as their voltage rating is okay... I will keep them in mind!

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arvidb
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03 Aug 2022 22:44 #248982 by arvidb

Replied by arvidb on topic How do you pass shielded servo motor cables through the cabinet wall/panel?

tommylight wrote:
I just put those plastic/pvc round thingies to protect wires from scratching.

This sounds pretty tempting!

Easy, and if it works then why not? How do you connect any cable shields though? Do you clamp them to some ground bar or something? Or just use a pigtail at the drive?

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How do you pass shielded servo motor cables through the cabinet wall/panel?

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