What is meant by 4-core CY cable?

I'm sorry for asking this if it has been already asked but what does everyone mean when we are advised to use 4 core CY cable when wiring 8 cable stepper motors in parallel? My understanding of 4 core CY cable is 3 numbered black conductors + a green/yellow earth which is in the outer layer plus the screen. Surely I need to buy 5 core CY cable so the stepper coils are wired with the black conductors?

BTW Jazz, John S, Lee and Jonathan the build of my Ali gantry style router is about to start! So thanks to you guys for the help and patience and to all who have helped me on this forum in the last 3 years! Thanks Lee for the steer on reasonably priced circular saw blades for Alu

Mike

The colours don't matter, the electricity does not care about the colour of the cable so 4 core cy cable has 4 cores as you have stated all of them are separate from the screen. The screen should be earthed at a star point (where all the earths are connected together to avoid any ground loops in the control box) you only need to earth one end of the cable, depending on the size of the motors I use 1mm others use 1.5 mm. Good luck with your build. ..Clive

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Originally Posted by Clive S

The colours don't matter, the electricity does not care about the colour of the cable so 4 core cy cable has 4 cores as you have stated all of them are separate from the screen. The screen should be earthed at a star point (where all the earths are connected together to avoid any ground loops in the control box) you only need to earth one end of the cable, depending on the size of the motors I use 1mm others use 1.5 mm. Good luck with your build. ..Clive

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Thanks Clive for the prompt reply. I am using the Zapp Kit 1 ( NEMA23 3Nm Steppers, 36 volts 4.2A) so I guess 1mm2 should be ok and connect the screen at one end only (the control box) as you said. I will be using 4 pin XLR plugs and chassis sockets as they seem to have good contact surfaces and provide some locking to prevent accidently being pulled out! Found 4 pin XLR plugs at Maplin, but no sockets! Ebay to the rescue again and sourced 3 pairs reasonably priced.

Regards
Mike

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Originally Posted by MikeyC38

I will be using 4 pin XLR plugs and chassis sockets as they seem to have good contact surfaces and provide some locking to prevent accidently being pulled out! Found 4 pin XLR plugs at Maplin, but no sockets! Ebay to the rescue again and sourced 3 pairs reasonably priced.

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Let me just say that unless you intend to move this machine about often then I wouldn't use any connectors. Wire direct from motors to control box to lessen any potential for poor connections and places for bad joints. These type of connectors are one of the prime trouble areas after newness as worn off and cables weight starts putting stress on connectors and pins. They where never designed or intended to be left permanently connected and are meant for short term quick release and connection for the music industry.

Have you bought the Zapp Kit yet.?

Yes about a month ago. Just trying to clear the decks of home diy jobs so I can have a clear run at this

What type of machine and specs are you thinking of building as you could possibly get better performance with a higher voltage power supply with those motors. .. Clive

For future reference, YY is pretty much the same as standard flex, CY has mechanical protection in the form of tinned copper braid and SY has mechanical protection in the form of steel braid. CY is rated low to medium protection and SY rated as medium to high protection. This is what I've always been led to believe, however I could have been misled.

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Originally Posted by Clive S

What type of machine and specs are you thinking of building as you could possibly get better performance with a higher voltage power supply with those motors. .. Clive

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Hi Clive. I will be driving 1605 ballscrews on all axes 1100 x 700 x 300 nominal flying gantry style router from alu plate and extrustions (see pic attached)
Attachment 12861

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Originally Posted by LawcockLD

For future reference, YY is pretty much the same as standard flex, CY has mechanical protection in the form of tinned copper braid and SY has mechanical protection in the form of steel braid. CY is rated low to medium protection and SY rated as medium to high protection. This is what I've always been led to believe, however I could have been misled.

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You should only use CY for CNC equipment, especially the connections to moving parts, as the SY isn't flexible enough. Here's the official blurb, taken from http://www.bs6500.co.uk/

"Control Cables
YY Control Cable, SY Control Cable and CY Control Cable are flexible instrumentations cables – with a voltage rating of 300V/500V – designed for use as an interconnecting cable in signal and control equipment – for measuring, control or regulation.
http://www.bs6500.co.uk/img/YY%20Control%20Cable.jpg
YY Control Cable to BS6500
YY Control Cable is a multi-core cable with class 5 stranded copper conductors, PVC insulation and a grey PVC sheath. YY Cable is also referred to as Unscreened, Flexible or Unshielded Control Cable and YY Control Flex. Projects in public buildings, such as offices, schools and hospitals will specify a LS0H version of YY Cable. Similar in construction to the YY PVC Control Flexible Cable, the LS0H YY Flex uses XLPE insulation and a grey LS0H sheath in place of PVC layers.

http://www.bs6500.co.uk/img/SY%20Control%20Cable.jpg
SY Control Cable to BS6500
SY Flex is a built in much the same way as YY Control Cable – with class 5 flexible annealed plain copper conductors, PVC insulation and a transparent PVC sheath. SY Control Flexible Cable has the added benefit of a galvanised steel wire braid with PVC bedding for mechanical protection so it can cope with situations of medium to high stress. SY Cable is also known as Flexible or Braided Control Cable, and SY Control Flex.

http://www.bs6500.co.uk/img/CY%20Control%20Cable.jpg
CY Control Cable to BS6500
CY Cable is a flexible multi-core cable with class 5 flexible plain copper conductors, PVC insulation, a plastic core wrap, a tinned copper wire braid and a grey PVC sheath. The construction of a LS0H CY Control Cable differs slightly – XLPE (Cross-Linked Polyethylene) insulation and a LS0H sheath are used in place of the PVC layers. CY Cable is also known as Instrumentation Cable, CY Flex, CY Control Flex, Robotic Cable, Copper Screened Control Cable, Shield Control Cable, Motor Cable, Multi-core Cable and Screened Cable."

Very informative, thank you very much.