stepper are not moving

the steppers on my ramps 1.4 board are not moving but binding when powered. i am using KV4242-N2B007 steppers from Nidec. i am supplying 12v 30A to the ramps board. most of the parts from my 3d printer come from a davinci mini w. I feel like i am missing something obvious in the configuration but i don't know.

Quote
shellman3379
the steppers on my ramps 1.4 board are not moving but binding when powered. i am using KV4242-N2B007 steppers from Nidec. i am supplying 12v 30A to the ramps board. most of the parts from my 3d printer come from a davinci mini w. I feel like i am missing something obvious in the configuration but i don't know.

There are a few possibilities, but assuming nothing is broken, the most likely reason is the stepper cable wiring order.
FIRST, make sure that you have the stepper controllers correctly installed. A Google search will answer that question.

OK, time to explain how to tie shoe laces...

Connect the cables to your steppers.
For the most common stepper controllers (my A4888 (red board) and DRV8825 (purple board) for instance) you want the 4 pin connector wired thus

[A1][A2][B1][B2]

Other stepper controllers may want a different configuration. Check your stepper controller documentation. Google around, you'll find it.
[edit] If the stepper goes the wrong direction, either swap either of the stepper winding wires or edit the printer code to reverse the direction of that stepper.

A and B refer to winding pairs. The bipolar stepper has two "coils", A and B. Use a digital volt meter set to measure resistance, on the continuity setting (marked with musical notes). When you touch a winding pair, you will get a beep. It doesn't matter which winding pair goes where. on the connector shown above.

If you are DIY building a printer or from a kit, you SHOULD have a DVM, this is an essential tool. If you don't have a DVM you can still find the winding pairs.
Turn the stepper shaft with your fingers, feel how much effort this takes.
Grab a wire that will fit into your 4-pin connectors, use this to short two of the wires together (any two wires).
Now turn the stepper shaft. If the shaft is now harder to turn than it was without the short, then you have found a winding pair.

Arrange your wires according to the connector order shown above.
This can be tricky and you can easily ruin your connectors, so be careful.
I use either a pair of sharply pointed tweezers or a hobby knife (Exacto knife) to either gently lift the plastic tab or press down the retaining tab on the pin to let the pin slide out.
When you look at the connector, you'll understand what I just wrote above. If you have to press down a retaining tab to get the pin out, you will have to bend it back. use the hobby knife to gently lift the tab back up.

Now you will have rearranged your pins. You will see the steppers turn, and most likely, you will feel them getting very warm. You need to adjust the current limits using the the metal trim pots on the stepper boards.
Remember that DVM that I said you needed? Well, you can't do this step without it, and you are likely to damage either the controllers or you steppers if you ignore this next step, and you will need the DVM, and you will need to know how to calculate the correct setting, for that you will need to get the data sheet for your controller. I think Pololu does a good job explaining the formulae for calculating current. It is different for different boards. The last set that I just adjusted was for the DRV8825 controllers - current in amps = volts measured X 2. Check the data sheet. Check your data sheet to see if you have to do the adjustment with or without the steppers connected.
The easy way to do this is to also use a pair of alligator clips and a wire with a single pin connector on it, AND a metal, flat blade tuning screwdriver, one slightly larger than what you would use to tighten the screws on your glasses.
Find the data sheet for your stepper motors to find the maximum winding current, then back off from that. I have some steppers that have a 1Amp max current, I set them up for 0.8 Amps as a trial value. Google for what others use on a similar printer, or if your initial setting causes your printer to too weak and skip steps, fiddle with it until you get good performance. In general, higher current means stronger motors, which typically translates to faster motors as well, but it is generally wise to stay away from the very maximum value.

Plug the single wire pin onto any GND (-) pin on your board, connect an alligator clip lead on that wire and the other end of the clip to the negative (black) wire on your DVM.
Clip the other alligator wire clip to the red (+) wire on your DVM and set the DVM to measure DC Volts on the 20V setting. Clip the other end of that wire to someplace convenient on your tuning screwdriver.
Turn on your DVM, yeah, dumb instruction, but you know...
Turn your Arduino/RAMPS board set on.
Adjust each tuning pot to the setting you want. That metal pot is also the spot to measure while you are tuning - with the wires connected as I said, you will instantly see what you are setting the voltage to.
BE CAREFUL and do not let that screwdriver touch any other component on the controller board, that may short something out.

Now you have your steppers set up to run.

have fun,
DLC

Edited 3 time(s). Last edit at 09/23/2022 12:39PM by dlc60.

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