Re: Drive mfrs recommendations for MOTOR cables ?

Peter,

Good points. I would add the following:

(1) Use stranded wire. Solid wire is prone to fatigue failure if it
is repeatedly flexed.

(2) Use strain relief where flexing will occur. This means using some
type of cable retention at both ends of the bending radius to prevent
flexing at connectors or soldered joints.

(3) Keep the flexing radius as large as possible to limit stress
concentration.

(4) Treat any soldered wire as if it were solid wire. Do not flex it
or it will rapidly fail.

(5) Do not nick wire strands when stripping wire. Nicked (or missing)
strands are stress concentrators. The wire will fail at the nicked
location if it is repeatedly flexed. If strands are nicked when
stripping the wire, discard that end and do it over again.

(6) When solder-tinning stranded wire, make sure the tinning is
uniform all the way around the wire. You should still be able to see
the strands on properly tinned wire. The solder should wick into the
insulated end smoothly.

(7) Use rosin core solder.

Mariss

--- In CAD_CAM_EDM_DRO@y..., Peter <prenolds@s...> wrote:
> I'm not a drive manuf. but I am an EE and please don't let's go
down the
> "monster cable" and gold connectors like certain gullible
audiophiles...
> And don't get me started on oxygen free copper... arrghhh!
>
> In addition to the various questions raised, you'll notice that
Mariss
> has said on several occaisions "use the largest wire that will fit
in
> the connector. For pretty well all the stepper/servo applications
you
> listed and that are contemplated by this group, a 16 Gauge or 18
Gauge
> conductor will be just fine. Ease of handling/terminating is an
> important factor. Mechanical durability is also important. Too
thin a
> conductor and it may break if you walk on it, drop something on it
etc.
> If you can, purchase a multi-conductor cable - it looks better
and is
> more durable.
>
> Keep the conductor as short as is reasonable between controller and
> motor but remember copper isn't real stretchy so allow some slack
for
> motors mounted on moving tables. 8 feet should not be a problem,
80
> feet probably would justify a heavier wire gauge.
>
> Minimise the number of connectors between the motor and the
controller
> and take good care when you are terminating a cable to a
> connector/motor/power supply. Intermittant connector faults will
drive
> you crazy. You'll need some connectors to
disconnect/service/maintain
> your equipment - just don't go overboard. Also, make sure the pins
are
> rated 6-10 amps each (or parallel a couple of pins if they are
lower
> current rated). FYI, a D-Sub connector pin typically carries 3-7
amps
> "per pin" according to the AMP/Tyco datasheet but officially, you
can't
> terminate anything bigger than a 20G conductor.
>
> Shielded is good, but not essential. For peace of mind, I use foil
> shileded cables grounded at the controller or power supply end only
to
> avoid ground loops. Foil and braided shielding is better but
probably
> overkill for most apps. I found less noise on some power lines
after I
> installed a braided shielded power cable between my VFD and spindle
> motor (7' of shielded cable purchased by the foot from McMaster
Carr).
>
> Wire/cable that is too big can't hurt your motor, only your wallet
(or
> purse??) and also requires bigger connectors which also cost more.
>
> I hope this helps.
>
> Looking forward to NAMES...
>
> Cheers, Peter
>
>
> batwings@i... wrote:
>
> > At 08:52 AM 4/26/02 -0000, you wrote:
> >
> >>Hello Dan, Dean, Mariss, Hans, Tim,?,?,
> >>
> >>I'm wondering what our list member step drive mfrs recommend
using
> >>for cabling FROM their drives TO the motors?
> >>
> >
> > Order your motors with cables. Mine came with about 8 feet
already hung.
> >
> >
> >>Shielded?
> >>
> >
> > Not needed.
> >
> > Individually? Overall? Braided? Foil?
> >
> > Straight-laid cable.
> >
> >
> >>Effect of wire that is "too big", if there is any?
> >>
> >
> > Saves power but costs more.
> >
> > Regards, Hoyt
> >
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