Motor Cable Faults

[AeroKam]

Hi all,

I am having a real problem with breaking cores in the cables I have used for the motor drives and limit switches on my 1200x 1800 3 axis machine. I have obviously purchased the wrong type of cable from a supplier (who was supposed to be an expert!). I have had 3 breaks in the last 4 months. The faults start as an intermittent fault and gradually get worse. Not a happy tale! This is a bummer as I payed many hundreds of dollars for the cable now I will have to re-cable the entire machine.

Can anyone give me advice on the name/type of cable I should have used and/or an Australian supplier who really knows what they are talking about.

I am a bit frustrated as my machine works beautifully apart from this problem.


Regard,

Bruce

[Al_The_Man]

You have to give a bit more info, what is the environment? What is the application, i.e. typical cable carrier, e.g. Igus etc?
What cable are you using now that is failing and where is it failing, mid length or at the connectors?
Three breaks in 4 months is rather drastic for a recommended cable?
Al.

[AeroKam]

I am using cable chain to support cables on X and Y Axis in the traditional way, looping back on itself. Cable seems to be breaking on the bends ie. the continual opening and closing of the radius of the cable chain as the axis moves back and forth. I think I have been sold a good quality cable ie. good mechanical strength, good shielding but not good flexability. I will try a the local Allen Bradley dealer and see what they can suggest.

[Al_The_Man]

SuperFlex and kabelschlepp are among the best, I believe they show availability in Australia.
If you can get Belden and Alpha, they should also be able to supply you.
But the secret is to get the maximum strands per conductor.
Too few and you get fracture.
Al.

[AeroKam]

Just got a price on igus cable $12.50/mtr !

it would cost me $1000 Plus to rewire my machine - to expensive

[Rodm1954]

$1000 is 80 metres of cable at $12.50/m
Something wrong there

[AeroKam]

2 x drives ,1 y drive, 1 z drive, 2 x limits, 1 y limit, 1 z limit, 2 E stops on gantry. It all adds up.

Bruce

[robwhi]

Bruce

You need to give me your specs to give you better advise
Ie what Voltage and amps . Is it mains rated ?
Sounds Like you also need shielding?.

It is very important in a flexible situation you use Multi strand cable with most stranding available. A good tough insulation like Polypropylene will also prevent kinking and tight bending as well.

What cable are you using at the Moment?

Cheers

Rob

[jestah]

Hi

I am also a bit unsure as to what cable i will need and would appreciate your advice. I have 4 68v stepper motors and a power supply that will supply a peak of 14A. The longest axis will be around 7m of cable from motor to controller.

thanks
Jestah

[robwhi]

Hi Jestah

It is a bit hard with out seeing the actually application

If you are running 14amps Directly you will need at least 1.5mm cable

How many cores do you require ?

How much is it going to flex and bend ?

I would recommend a high multistrand cable with a tough insulation without further info.

Sometimes it is far better to run single core cable in a nylon conduit as it avoids point bended of the copper and also lets the cable slip which also avoids the point bending (kinking). All the big CNC manufacturers use this method

Also very important in a flexible or vibration area to stay away from soldering your connections


Cheers

Rob

[Zig]

Bruce,

Dont know who You have been talking to.

At the risk ofpointing you to Your original supplier try TREOTHAM who su[[ly specialty cables for NC instalations.
Else if that fails for You there is a small specialty cables mob in Brisbane who do only cables.
Evolution cables, Rick Coert 07 3205 2660.

Good luck and keep us informed

[MysticMonkey]

Just going to reiterate what everyone else said

Treotham for the Igus engergy flex or RS for convenience
A high multistrand cable for flexibility - check RS Components

The normal flex for extension cables might work if each motor draws under 13A - but even these do break eventually

The Insulation might not be ok for harsh environments