Melted wires
-
I am still proto-wiring my setup before creating final wiring harnesses.
I noticed one of the motor's jumper wires have melted. Is that just a jumper wire issue, or should I lower the stepper motor current?
-
Likely a bad crimp on that one pin.
-
@jens55 I would hope so, but it has happened on all of my stepper motor wires..
-
That's a bit different than the initial picture but it is still odd that the mating connector shows no issue of heat.
I can say from first hand experience that a standard Dupont connector is limited to maybe 2 amps or so. I have melted them at just under 3A. If these were commercial jumper wires then the wire was likely undersized for the use in a high(ish) current use.
In a situation where you are just trying to set up things, I would reduce motor current until I was ready to make connections permanently.
I would suggest 20-24 ga wire for 2A and if you are going higher then use 20 to 22 ga.
I would actually discourage the use of dupont connectors for this use but you could get away with it. It's a balancing act and as always, YMMV. -
@jens55
Would this be a better option? it says it is 14g
https://usa.banggood.com/1M-4pin-Stepper-Motor-Cable-XH2_54-Male-Compatible-For-3D-Printer-p-1118480.html -
@pyper that is the weight and not the gauge of the wire! It does say 2A though.
I would go back to square 1 - what is the current rating of the stepper motors you are using? Do you need a fully prepared cable or can you put on connectors yourself? What controller are you using?
I can't speak for the connectors that are on the motors, are they the same as the connector on one end of that cable you list? What are the connectors on your controller and is that what is on the other end of that cable? -
It seems like you're using dainty little dupont jumper cables intended for arduino prototyping to push some higher motor current.
You haven't told use what motors or what current you have the driver set to. Get better cables.
-
@phaedrux Second that.
-
@lodger, you can only third that since Phadrux has second it and I have first it ....
-
@jens55
I was using 1.2A, but have lowered it to 800ma which seems to have helped.
I was just surprised these jumper wires melted, they are indeed dainty. I'll get some better cables! Sorry about all the confusion -
No problem. The rule of thumb for motor current is to target 60-85% of the motors rated max current for best performance, balanced for heat and noise.
I'm also surprised it melted. If you clip and strip the wire, how many conductors are actually in the wire?
-
@phaedrux, conductor count is actually quite common and the same for the vast majority of wires. When you get into a larger qty of individual strands you are getting into specialty wire such as silicone insulated or test leads or some such. Marine wire has a common higher strand count to make it more flexible. The 'standard' is 7 conductors and the gauge of those conductors changes to achieve the overall wire gauge.
The other thing that plays a roll in the over heating is the contact resistance between the two connectors. Since these connectors are not spec'd to fit together, there is a good chance that you have only a tiny contact surface which then generates heat. Add to that the use of chinesium and you never know what you got
