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8 wire stepper - a real pain

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fuper

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I've got a functional unipolar stepper driver that drives a 5 wire stepper. It's a cd4070 and a cd4027 with 4 TIP31 for the transistors.

Its a neat circuit: https://www.aaroncake.net/circuits/stepper.asp?showcomments=all

Anyway - I have a lin engineering 5718M-05E-05 It's an 8 wire stepper.

Using my ohmeter I've figured that there are 4 sets of wires. For the life of me I cannot get the circuit to drive this stepper at all. I can get it to do the vibrate, go forward a step then backward a step in a loop etc basically indication that I've not groked the wiring.

Anyway - these steppers are showing up on Ebay and I thought I would pass it along that I'm having difficulties. I've worked about 8 hours on this now with no success :(
 
patience

An 8 wire is "usually" a 5 wire without commons tied. Most I've seen have color coded leads, where the lighter color of any pair can be considered the same pole.

This is if you want to deal with it in a conventional step mode. Polarity access allows "micro-step" rotation control. More overhead .... better control.

If not: I'd take a "soft" power (rated power thru a resistor/current limiter) feed to play the guessing game. Eventually you'll find the proper sequence. I've never had to do this... diligent spelunking "usually" uncovers the insight of wiring scheme. Good Hunting...<<<)))

Oh, and when first dealing with Any stepper: slow the step speed A LOT until you're Certain the sequence is correct.
 
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Hi,

the 5718M-05E-05 is a unipolar stepper motor.

Just connect the wires according to the spec sheet.

Boncuk
 
Hi,

You should tie together one wire of each coil. This will be the fifth wire that will eventually be plugged to the +12V of the driver power supply. According to the datasheet of your motor those wires could be: RED, ORANGE, YELLOW and BLACK.

Now, to find the proper sequence, use a 9 volts battery and plug those 4 wires to one side of the battery and by touching the other side of the battery with each remaining wires, one after the other, you will soon find the sequence. Putting some scotch tape on the axle will help.

(My guess is : RED/WHITE, YELLOW/WHITE. ORANGE/WHITE and BLACK/WHITE but I could easily be wrong.)

This motor could be run as an unipolar or as a bipolar motor.

The driver is unipolar and I am guessing that It will give only a full step sequence, that is always 2 phases energized at the same time.

The sequence would be like this:

XX00
0XX0
00XX
X00X

With this driver, the motor could not be run from the 12v. supply without a proper ballast resistor.

Here is some little drivers that I made using the same logic chips: https://www.youtube.com/watch?v=BAvMMzYG5r4
Alain
 
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Thanks everyone for the replies!

I finally got it to work, like the previous gentleman said - I just had to follow the datasheet for the motor :|

What was complicating things for me was:

My original power supply was [a home built variable benchtop unit I built] was only putting out 400 ma. These steppers can draw 2 amps. Some of the inconsistencies I was seeing was due I think to insufficient power.

I didn't have enough caps around the ICs. This made the sequence much smoother. I was doing this on a breadboard which I understand to be noisy.

Here is how I got this to work -

I followed the LIN datasheet for 8 wire unipoloar. I tied all the comms together. The circuit that I referenced previously attaches like this:

Q1 -> Blue/White
Q2 -> Red
Q3 -> Green/White
Q4 -> Black

Tie Black/White with Green to V+
Tie Red/White with Blue to V+
 
Ballast Resistor

Hi,

You should tie together one wire of each coil. This will be the fifth wire that will eventually be plugged to the +12V of the driver power supply. According to the datasheet of your motor those wires could be: RED, ORANGE, YELLOW and BLACK.

Now, to find the proper sequence, use a 9 volts battery and plug those 4 wires to one side of the battery and by touching the other side of the battery with each remaining wires, one after the other, you will soon find the sequence. Putting some scotch tape on the axle will help.

(My guess is : RED/WHITE, YELLOW/WHITE. ORANGE/WHITE and BLACK/WHITE but I could easily be wrong.)

This motor could be run as an unipolar or as a bipolar motor.

The driver is unipolar and I am guessing that It will give only a full step sequence, that is always 2 phases energized at the same time.

The sequence would be like this:

XX00
0XX0
00XX
X00X

With this driver, the motor could not be run from the 12v. supply without a proper ballast resistor.

Here is some little drivers that I made using the same logic chips: https://www.youtube.com/watch?v=BAvMMzYG5r4
Alain

Thanks for the reply. I'm going to switch to TIP121 and see if the built in Diode will work here. mydiycnc uses the same circuit but uses a L293 for the power amplifier.

Can tell me more about the ballast resistor?
 
On my last post, I think that I was not referring to the good datasheet for your motor.

Anyways! Here is how I would calculate the value for the ballast resistors:

Suppose that you want to use a 12 volts power supply, the motor is rated at 2 amps and the resistance per phase is 1.8 Ohm. By Ohm's law (V=I*R) the voltage for the motor is then 3.6 volts.

so 12 volts
minus 3.6 volts
gives 8.4 volts
minus 1.4 volts for the TIP121 voltage drop (TIP31 would be 0.7 volts)
equal 7.0 volts

So 7 (volts) divided by 2 (current) gives 3.5 (Ohms) R=V/I
and 7 (volts) mulitplied by 2 (current) gives 14 (Watts) P=V*I

So one resistor, the nearest value of 3.5 Ohms, 14 watts betwen power supply and Black/white tied to green and another one between power supply and red/white tied to blue.
(For the TIP31 the resistors should be the nearest from 3.85 Ohms, 15.4 watts.)
 
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