6 wire steppers motors

mikediv

Hi guys I have some old 6 wire stepper motors I saved from some old copy and print machines for the life of me I can not get them to work
one is a Vexta 2 phase 6 volt 6 wire stepper I built a circuit with a prop chip and an ULN2803 it will drive the Parallax servos the ones that come with the BoeBot 3 wire
but when I connect to the steppers they do nothing I have traced the pins to the 2 coils and the center taps I am sure of my wiring
anyone have a basic wiring diagram for a very simple 6 wire stepper interface??
Also I can see the PWM on my oscilloscope so I know the circuit is working what am I missing?
Thanks

Prettybird

Did you try to google the motor mfg. and part number? Sometimes I have gotten lucky on unknown parts.

LoopyByteloose

Interestingly a 6 wire shoud be able to reconfigure as a 5 wire or a 4 wire. So you should be able to do something.
Also, there is a logical sequence of switching wires to get one working if you have no idea which wires are which.

I'd have to dig out some paperwork to explain, but searching the web for DIY stepper wire info is helpful.· The book "CNC Robotics" by Geoff Williams·is quite helpful and can be gotten very cheaply second hand [noparse][[/noparse]at Abe Books].· Try the public library as well.

Nonetheless, the ULN chip is just for a smallest of stepper motors. Even at low voltages, you can have some serious demands on amps that will fry the chip. So you might try to get specs or at least measure the coil resistance and reverse engineer the power requirements.· Overvoltage is generally not a serious problem as the enamel wire is usually far better insullation than required.

But beware that·overamperage for the enamel wire size will melt the internal coils.· E=IxR and P=IxE will pretty much bail you out if you use them intelligently. You may be underpowered.

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Ain't gadgetry a wonderful thing?

aka G. Herzog [noparse][[/noparse] 黃鶴 ] in Taiwan

Post Edited (Loopy Byteloose) : 5/28/2009 2:45:03 PM GMT

Franklin

Could we see a circuit diagram? Steppers don't use PWM directly.

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- Stephen

mikediv

Actually got it to work but I would like to know what you guys use to post schematics? I have Proteus 7 , B2Spice , NI with Labview and circuit design suite 10 but when I tried to attach to my schematic it would not work???
I have needed on more than one occasion to attach my drawings any suggestions?

I ended up using the ULN2803 with my propstick that's all to get the Vertex 2 Phase stepper to work

Pins 2,3,4,5 of the ULN went to the Propstick pins 0-4 pin 9 of the ULN to ground pins 14,15 went to one side of the stepper coil green and black wire pins 16,17 went to the other stepper coil wires blue and red
the center taps of the stepper coils white and yellow wires went to the ULN pin 10 , ULN pin 10 also went to 12V and had a 12 Volt Zener before the stepper center wires.
Pin 1 of the ULN went to +5 volts , the Vertex stepper as big as it is in only 6 volt but 2A max draw I had no load on it
I didn't buffer the prop output pins I just attached them to the inputs of the ULN I did add shunt diodes on the ULN outputs to kill the noise it looked really bad on the scope even though it worked you could see lots of noise the shunt diodes cleaned it right up
I could find no code for steppers in the Prop Objects downloads so I basically just output a Square wave on pins 2,3,4,5

kwinn

I think what you have may be bipolar steppers. if you read low or no resistance between 3 wires and very high to the other 3 wires that is almos certainly what you have. They may run wired like normal steppers but the torque would be very low.

Leon

The Pulsonix software I use has a screen capture function which puts the schematic on the clipboard. I paste it into MS Paint and save it as a GIF. I then upload it to my website and use the URL in my post with [noparse][[/noparse] img ] [noparse][[/noparse] /img ] round it (remove the spaces).

Leon

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Amateur radio callsign: G1HSM
Suzuki SV1000S motorcycle

LoopyByteloose

Eagle CAD offers a good free schematic frontend and if you want to make PCBs later, you can do small ones for free.
But like all CAD, there is a bit of an initial learning curve.

Some people use the characters offered in Parallax's SPIN font and cut and paste. For quickie postings, that's terrific. Parallax provided it just for posting here.

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Ain't gadgetry a wonderful thing?

aka G. Herzog [noparse][[/noparse] 黃鶴 ] in Taiwan

kwinn

I use paint unless I intend to make a PCB. I have a drawing with the components, and simply cut and paste what I need. Being able to choose different colors for connections, buses, and components is a great help. The first time I used it I was trying to decipher a very poorly done and water damaged schematic to repair some equipment. Paint was all I had available at the time, and it worked so well I continued to use it.

mikediv

Thanks guys I do use the one in the parallax IDE its very good for simple stuff , Kwinn I have 2 Phase Unipolar steppers

The Vertex I have docs for the Shibaura I just ohmed out , there is a very good link on using the ULN2803 .
Following the color code for the Vertex is as follows between the pair's yellow , black, green , yellow is the center tap from yellow to iether black or green is 4 Ohms from black to green its 8-10 ohms
Same for the other winding red, blue, 8-10 ohms white is the center tap 4 ohms to either red or blue