Cabling a CNC Router

**CraftyGeek** · 20-10-2009

That helps a lot thanks, I'll order some cable & other bits later - but it also brings up another issue that I hadn't really thought about too much.

My motors are rated at 2.5A per phase & my controllers are also rated at 2.5A.

So my basic knowledge of electronics tells me that I should wire the motors as serial to match the controllers. But I see some mention in that thread of that having an impact on the torque of the motor.....so should I really be looking at running in parallel with a resistor? (I guess that ohms law applies here)

**irving2008** · 20-10-2009

Originally Posted by CraftyGeek

That helps a lot thanks, I'll order some cable & other bits later - but it also brings up another issue that I hadn't really thought about too much.

My motors are rated at 2.5A per phase & my controllers are also rated at 2.5A.

So my basic knowledge of electronics tells me that I should wire the motors as serial to match the controllers. But I see some mention in that thread of that having an impact on the torque of the motor.....so should I really be looking at running in parallel with a resistor? (I guess that ohms law applies here)

Which motors and drivers? And no, ohms law doesnt apply - motors are inductances. Motors can be spec'd as 2.5A/phase "Bipolar parallel" or 2.5A/phase "unipolar" so saying 2.5A/phase without saying how they are wired isn't necessarily meaningful.

**CraftyGeek** · 20-10-2009

Maybe I wasn't clear enough above.

The motors are 4.5v, 2.5A per phase to be wired bipolar.

I was originally thinking of wiring them as serial to match the 2.5A controllers, but after reading the other thread it mentioned that you get greater torque if they are wired in parallel - that would, I presume, double the current being drawn from the controller - thus needing a resistor to limit the current (ohms law).

The motors are from Arc Euro Trade - 180Ncm (can be used bipolar or unipolar)
The controllers are the Routout 2.5A ones

The power supply that I currently have to hand is 12-14V (varies a tad under load) @ 10A.

I will get a better PSU at a later date, probably around the 25v mark.

**irving2008** · 20-10-2009

Originally Posted by CraftyGeek

Maybe I wasn't clear enough above.

The motors are 4.5v, 2.5A per phase to be wired bipolar.

I was originally thinking of wiring them as serial to match the 2.5A controllers, but after reading the other thread it mentioned that you get greater torque if they are wired in parallel - that would, I presume, double the current being drawn from the controller - thus needing a resistor to limit the current (ohms law).

The motors are from Arc Euro Trade - 180Ncm (can be used bipolar or unipolar)
The controllers are the Routout 2.5A ones

The power supply that I currently have to hand is 12-14V (varies a tad under load) @ 10A.

I will get a better PSU at a later date, probably around the 25v mark.

Its hard to tell as Arc Euro dont say what mode they spec the current in, however the 3.5Nm motor is spec'd as a 4.2A/phase in bipolar parallel and they call that a '4.2A stepper' so I am guessing that yours is a 2.5A bipolar parallel. the way to check this is measure the resistance of one winding e.g. red to yellow - if it's 4ohm then you can run this bipolar parallel at 2.5A.

Whatever the motor spec' if you only have 12v power supply then I'd run this bipolar parallel at 2.5A. Bipolar series on only 12v is going to be very underpowered.

You don't need a current limiting resistor, the Routout drivers are chopper current limiting drivers... they wont let you draw more than the preset current limit (up to a maximum of 2.5A).