choosing the right stepper motors.

So i'm making my reprap with makerbots pre-assembled gen3 electronics. i don't know much about electronics in general,

I have already tried a motor from ozxmods.com.au and it won't start up when i hook it up to the driver. I tried hooking the colours up as according to the wiki instructions then later realised that the wiring of the ozxmods were different (they use the same 4 colours but in a different order)... i hope this didn't blow something...

When i put the multimeter to the A&B or C&D pins of the drivers, i only get .01 of a volt. This can't be right can it? I'm pretty sure my power supply is working fine and the LED on the driver is on.

i've compiled a list of the motors available to me from Australian websites and their specifications, next to makerbot's specs.



So yeah the ozxmods one doesn't work, does anyone know if any of the others would be more likely to work or if my problem lies with the driver itself?

Edited 1 time(s). Last edit at 02/08/2010 03:06AM by mlagana.

my ausxmods motors work perfectly, and according to the table you pasted are the most suitable of all your options by a wide margin. sounds like your driver isn't working properly for some reason- is the enable line connected?

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Wooden Mendel
Teacup Firmware

i'm not sure what that is...

i tried it with the driver plugged into the mother board and no luck if that's what you mean

is enable line one of the pins that the idc connects to? i read about pulling it high or low... is that a software or hardware thing?

it should be pulled low by the firmware.

can you be more specific about what the motor does and doesn't do? "doesn't start up" is not helpful. does it become more difficult to turn when power is applied to the driver? does it make any noises? does it become warm? does the chip on the driver board become warm? what do the lights do? what does the software you're using tell you?

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Wooden Mendel
Teacup Firmware

it just doesn't do anything at all, no noises, no warmth.. if i turn the motor manually the leds around the idc pins light up.

i'm waiting on a USB->TTL cable, so i haven't tried any software yet. I thought it already had firmware to test the motor, but i guess i'll have to work on other things until my usb cable arrives.

others have reported those symptoms with enable line not connected or not pulled low. what are you using to send signals to your driver?

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Wooden Mendel
Teacup Firmware

Nothing. was just going off this: test your board

i was under the impression you only needed to connect the stepper to the driver and the driver to power and then "After a few seconds, your stepper motor should spring to life."

but i'm relieved to find out that it's most probably a firmware thing, not fried electronics or anything!

thanks for your time and help triffid.

Sorry to budge in on this thread, but I have a very similar question, so I hope it is ok, otherwise, I apologize in advance:

I have found some motors in the UK, which I hope to use, the pricing isn't bad and the shipping costs are good; but...
Step Angle 1.8°
Step Accuracy 5%
Holding Torque 4800g-cm / 66.66 oz-in
Coil Resistance 3.1V
Rated Current 1.25 Ohms
Motor Length 48mm
Mounting Plate Size NEMA-17
Shaft Diameter 5mm
Weight 332g
Number of Leads 4

So torque should be more than adequate, however the manufacturers specs says:
Rated Voltage: 3.1 V
Rated Current: 2.5 A
I was planning to use the Pololu stepper controler but the voltage on that one appears to be way too high, 8-25 volts, and it can only support 2A per coil.

Amp wise I was thinking about installing a fuse to protect the circuits, will that work? and what to do about the huge difference in voltage? or should I try to find some completely different motors?

the stepper driver controls current quite carefully, so feed it 12v and it will automagically drive the motor properly. My motors are rated 2.77v and that just means that my A4983 board can get them moving really fast from 12v

I've put the full explanation of this in numerous other threads so far, do a search.

ps: you must heatsink the A4983 if you want more than half an amp into your motors.

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Wooden Mendel
Teacup Firmware