OK, not exactly wiring, but where can I buy wires in US??

gnydick

I'm trying to find stepper motor cables that fit the 6HC, 20-16 AWG. Everything I can find is much too small and is not crimpable, even in the 18-22 AWG crimp terminals.

I'm ideally hoping to find pre-terminated cables where all I have to replace is the the driver end connector.

magnets99

that's odd, are you looking for the cables or the crimps?

16awg is pretty chunky and i'm suprised you're having trouble.

this is the datasheet for the headers used on the board
https://www.jst-mfg.com/product/pdf/eng/eVH.pdf

the notes say
"The 4 wire motor and OUT1, OUT2 and OUT3 are JST VH series connectors. They require a minimum of 22AWG wire (20AWG or 0.5mm2 recommended. Most NEMA17 size stepper motor wire will will not be thick enough to use in the normal way; but you can double the stripped part of the wire back on itself to bulk it up, and put a small length of heatshrink sleeving over the insulation to bulk up the insulation. You will need a suitable crimping tool for the crimp pins, for example Engineer PA21 (use the 2.2mm jaw opening to crimp the bare wire and the 2.5mm on to crimp the insulation). Alternatively you can solder the wire to the crimp pin"

If you are desperate and want it done now, that molex cables in your PC power supply for the older style hard drives are typically good quality 20awg stranded.

I often see PC's on council chuck out days to harvest.
Failing that i'd use mouser or RS.
Amazon or ebay will also provide what you need...but you roll the dice on quality.

gnydick

@magnets99 thanks. Lots of good information there.

gnydick

@magnets99 also, I'm so confused about the industry. Jst-ph tops out at 2A on 24AWG, but my motors take up to 2.8A.

How/why are motors made with connectors that can't carry the current they're rated for?

Superbrain8

for cables Igus.com is not bad. its a industry known manufacturer for motion system components. they make quite affordable cables too.
for cimping connectors mouser, digikey, farnell are common places to buy them from.
something to be aware of that a lot of cheap chinese clones have poor tolerances and potentially wont manage the current they are rated for.

for your stepper thing, look into Class H stepper they tend to have the wires hardwired to the stepper and take the connector out of the equation.

magnets99

@gnydick
I'm not sure but i would guess that because stepper motors use sine waves the rated current will be RMS not Peak. so you can add another 30% (terrible rule of thumb but it's good enough) which takes 2A to 2.6 peak, then a bit of headroom where the connector manufacture is being pessimistic and the motor manufacturer is optimistic.

or...

I'm not sure where you got those figures from.
the connector is a jst-vh (not ph) and is rated to 10amp with 16awg. But i would guess the limiting factor is more likely to be the trace on the board not the cabling or the connector.

gnydick

@magnets99 PH on the motor

Nurgelrot

Wire and crimps/housings. I use Newark (newark.com). They are in the the Mid-West US. But any reputable electronics supply will do. I happen to like their search functions but most of the other place have similar. Probably not the most economical in the small order numbers we typically need. But at least you know your getting the right parts.

magnets99

@gnydick
i'm afraid i don't know enough about stepper motors to say why. Are all nmea17's the exact the same? with the exact same connector?

dc42

@magnets99 it's common for Nema 17 motors to have 6-pin JST PH connectors on them, or else have no connectors and just wires. Unfortunately there are at least two different sets of pin assignments used by motors with these 6-pin connectors, so you must always check that you have connected them correctly to the Duet or other control board before trying to control them. If you get it wrong then the assumptions made by the driver as it tries to control the current fail and the current becomes uncontrolled. If you are lucky then the driver will detect that there is a problem and turn off; otherwise the result is a blown driver.

See https://docs.duet3d.com/en/User_manual/Connecting_hardware/Motors_connecting for how to identify stepper motor phases and connect them to a Duet.

magnets99

@dc42 yikes!
So less of a standard... More of guidelines really...