wiring gauge for a stepper motor

[falkpl]

This might be a little off the topic but I have a NI motion controller and I have 3 stepper motors to control.  2 motors are 1Amp and use a DB9 connector.  Can I use a RS232 campe (26 gauge) or do I need a smaller wire which would mean that I would have to make a custom cable for my power? 

Paul

[AnalogKid2DigitalMan]

Paul:

26 gauge solid, enclosed, can handle about 1.3 Amps, so it should do. Personally I would use 22 gauge for a good safety margin (5 Amps)

Smaller gauge =  larger cross sectional area = larger current capacity. Other factors are ambient temp, solid vs stranded, frequency, tinning, but a rough guideline in the link below.

http://xtronics.com/reference/wire_gauge-ampacity.htm

-Pete

[falkpl]

Thanks I figured I was going to need something in the ball park of 20-22 Gauge but I am a software guy so what do I know.  Do you know if some one makes a standard connectorized 22 gauge DB9 cable or do I have to get out the soldering iron.  I am trying to avoid reinventing the wheel since I have to make several of the same systems.

Paul

[Bill_5335]

You may have some luck with www.l-com.com 

Since I hate to solder, I use pins that are crimped onto the wire. I do a lot of custom cable so the crimper cost is justified. I use components from Amp.

[Buechsenschuetz]

Can I use a RS232 campe (26 gauge) or do I need a smaller wire which would mean that I would have to make a custom cable for my power?

I think "smaller" refers to a smaller AWG number. In the AWG system, a smaller number refers to a cable with LARGER diameter.

In a catalogue of a german stepper motor manufacturer it is stated that you should use at least 0.1 mm2 for each amp of motor current. Most, if not all, stepper motor driving modules have output current regulation. Since the current is the same at any point of a circuit (even at the end of a real cable with some ohmic resistance) the driver will always "push" sufficient current through the cable, provided that the supply voltage of the driver (usually 24V or 48V) allows for sufficient headroom.

Usually RS232 cables have something around 0.14 mm2 for each cable strand, so such a cable should be sufficient.

Living in Germany, I am not very familiar with AWG numbers and I do not have a conversion table from mm2 to AWG number handy - sorry.

You should also check whether the connectors you are using can handle the amps, but I thing DB sub connectors usually are rated at around 2 amps.

[falkpl]

Yes I mean lower gague which is larger wire.  22-20 gauge is what the manual ask for its 1-1.5 A.  I hate the two systems and would prefer if we all used metric but here in the USA its easier to work in AWG/english since it is sold at more suppliers.

[Buechsenschuetz]

Over here in Europe we have to live with both systems, too, since all crimping material and tooling sold by US manufacturers has markings for AWG numbers, and we have to convert them to metric dimensions to find the proper item for a certain wire.