X1 cnc wiring

OK, Arc Euro finally got the X1 long table back in so I can start putting together the X1 cnc converson. I have 3 amp steppers (57BYGH728-B), MSD 542 microstepping drivers and a
suitable 42v power supply all from Motion Control Products following good advice on here. Question is, I hear all sorts of fuss about 'noise' and 'ground loops' so should I be using shielded cabling for the steppers? They come with about a foot of trailing wires so does everybody just joint to them, open up the stepper and attach new cable or what? Pointers to a dummies guide would be welcomed. Cheers
--
Andy Parker
andy at agatehouse dot co dot uk
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On Thu, 12 Jul 2007 21:38:15 +0100, "Andy Parker"

Andy -
It's a good plan to shield the motor cables - as they are being driven by a pulse train at high currents, unshilded cables have the opportunity to interfere with signal cables (which should also be shielded. Ground them at the driver end only - the stepper body will be in electrical contact with the table, and via that, with the machine's eart, so if you ground the shields at both ends you are indeed creating a potential earth loop.
A neat way to connect the cables to the steppers is to attach a small plastic lidded box over the cable grommet on the stepper and run the cable in through the side (through a rubber grommet), make the connections inside the box (lose all but a few cm of the stepper's wires), srink sleeve over the solder joints, and you're done. RS do a range of lidded "potting" boxes that work well for this.
You should "star" wire (rather than "daisychain") from the power supply to the stepper drives. If you daisychain, then the second drive will see a varying supply voltage depending on how much current the first is taking, and so on.
In general, keep the signal cables as far from the mains and stepper cables as is practical.
Have fun!
Regards, Tony
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Tony Jeffree wrote:

http://home.lsces.co.uk/ModelEngineersDigitalWorkshop/wiki/?page 0NcmMotorTermination
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Lester Caine - G8HFL
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wrote:

That's the one. What you don't mention is that the plugs are 4-pin XLRs. These are pretty much ideal for CNC use - the pins are good for 10-15 amps depending on who makes them, so will cope very well with the range of amperages needed for NEMA 23 and 34 motors.
Regards, Tony
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Thanks chaps, rs duly instructed
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