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I have unipolar stepper motor with 6 wires and i have made controller circuit but when connect controller to stepper motor it is not working.. So i want to know weather stepper motor is working or not. Is there any simple method to test steeper motor? Thank you! enter image description here

ADDED: olin lathrop i have added digram. The other comination such as AB,AC, AD,BC,BD etc gives 50 ohms in multimeter.

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    \$\begingroup\$ It should be obvious you haven't supplied anywhere near enough information. My answer isn't really a answer yet. You'll have to cooperate and answer exactly what I ask and we can maybe get to the bottom of this. As it stands now your question is too vague and should be closed. Reply correctly and quickly, or else. \$\endgroup\$ – Olin Lathrop Jan 13 '12 at 15:17
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    \$\begingroup\$ Wait, you're using LEDs for backEMF suppression diodes? It's probably not what's causing your current issues, but it's a terrible idea. \$\endgroup\$ – Connor Wolf Jan 13 '12 at 15:44
  • \$\begingroup\$ @vijay, it is not an exact or else case, your question will get closed if detail is not added but questions can always be reopened if the issue is corrected, we just want the highest quality questions so that high quality answers that will be useful in the long term are given. \$\endgroup\$ – Kortuk Jan 13 '12 at 16:22
  • \$\begingroup\$ Your Ohm measurements don't add up. It would be good to see a diagram of exactly what you measured between what wires. This is with the motor disconnected from your circuit. \$\endgroup\$ – Olin Lathrop Jan 13 '12 at 17:37
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    \$\begingroup\$ You dd not do what I asked. I gave you a COMPLETE answer and you have partially ignored it. Why have you joined the black and white wires when measuring? If you do what I said you either will know it is broken or it will be working. \$\endgroup\$ – Russell McMahon Jan 14 '12 at 4:22
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Compleat Solution:

Identify two coils.
(1) If coils have no connection between them do "Main Test": below.

(2) If there is resistance measurable between windings provide a resistance map. as follos. 6 connections A B C D E F
Measure and report resistances AB AC AD AE AF BC BD BE BF CD CE CF DE DF

Main Test:

Coil 1 will have 3 wires A B C
Measure resistances AB BC CA Two combinations should measure R ohms. (R an arbitrary value) One combination should measure 2 x R ohms.
For combination that measures 2 x R ohms, name wire that is NOT connected = B

So now

AB = R ohms
BC = R ohms
CA = 2 x R ohms.

Provide voltage V+ which is voltage that stepper is rated at AND which can provide rated currrent. Power supplu has outputs V+ and ground.

Connect B to +V
Brush A against ground briefly.
Then brush C against ground briefly. Repeat A C A C.

Motor should jump backwards and forwards a smal amount on each touch of A or C to ground with


Coil 2 will have 3 wires DEF.
repeat as above for coil 1.
E = centre tap as above. Motor should jump backwards and forwards a small amount at each touch.

If no jumping then something is wrong.

If motor jumps do "Run Test" below .

Run Test:

Remove controller and put safely away for now.

Do following.
"Connect to" = electrically connect and leave connected. Disconnect = disconnect previous connection.

Windings are ABC DEF
B = centre tap
E = centre tap

Connect B to V+
Connect E t V+
These will remain connected.
Then

Initialise: Connect C to ground, Connect F to ground.

Run:

  • Disconnect C, Connect A to ground.
    Disconnect F, Connect D to ground
    Disconnect A, Connect C to ground
    Disconnect D, connect F to ground

Repeat from Run: above

Motor should go through one step cycle for the 4 steps above.

Report.

Fix controller.

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  • \$\begingroup\$ i cannot find even jerk in motor by doing so \$\endgroup\$ – vijay Jan 14 '12 at 3:37
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    \$\begingroup\$ Thre is no indication that you have "done so". I asked for ohm readings if it did not work but you provided and incomplete answer and joined wires when I did not ask you to. What voltage are you using? Dod you know wht voltage the motor is designed for. How do you know? What is it's model nuimber and brand (as asked for by Olin). Have you got a web reference. It is annoying to spend much time and give a complete answer and then have do something else instead but SAY that they did what was asked. \$\endgroup\$ – Russell McMahon Jan 14 '12 at 4:25
  • \$\begingroup\$ I have used tip122 transistor instead of bc547 as they mentioned in circuit. will it create a problem if i use new stepper motor.? \$\endgroup\$ – vijay Jan 14 '12 at 8:06
  • \$\begingroup\$ AB =25 ohms BC =25 ohms AC=50ohms i can read the same reading for coil 2 also. I have used 12V supply since in motor itself they mentioned 12V and torque 2Kg-cm. i cannot get more information about stepper motor which i am having because it is old one. and it seems no jerking in motor after following ur method also. \$\endgroup\$ – vijay Jan 14 '12 at 8:07
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First, make sure all the connections have continuity. If the motor has 6 wires, then it's probably two pairs of coils with a common wire for each pair. Use a ohmmeter to find which wire of each group of three is the common, and connect those wires to the positive supply. Then manually connect one of the remaining 4 wires to ground in sequence. You should see the motor jump a little each time you change wires.

If that works, the motor itself if OK and the circuit is the problem. If that doesn't work, then we need to know a lot more about the motor. Report on the result of the above and this answer can be expanded. A link to the motor datasheet would of course also help.

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  • \$\begingroup\$ i have checked the connectivity. i have identified the coil wire also... but even if connect motor directly to the supply i cannot feel even a jerk in motor \$\endgroup\$ – vijay Jan 13 '12 at 15:17
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    \$\begingroup\$ Show a diagram of what you found, including the DC resistances you measured for each coil. \$\endgroup\$ – Olin Lathrop Jan 13 '12 at 15:19
  • \$\begingroup\$ i dont have datasheet \$\endgroup\$ – vijay Jan 13 '12 at 15:21
  • \$\begingroup\$ wait i will add circuit diagram \$\endgroup\$ – vijay Jan 13 '12 at 15:22
  • \$\begingroup\$ I have used Tip 122 instead BC547... Is that a problem.. And regarding my motor It is 12V and 1A motor.. i have used dc adaptor of 12V and 1A.. can u help me now. I think probably i have given all information \$\endgroup\$ – vijay Jan 13 '12 at 16:05
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Follow these instructions properly if you want it to work:

If you don't want it to work then just keep doing semi-random things as desired :-)

What voltage are you using for stepper motor V+?
Why?


Disconnect black from white

Black and white are centre taps

Windings are of form

A - Black - B

and

C - White - D

Your next task is to assign colours to A B C D

Given coours for ABCD are Green Yellow Red Brown (order unknown)
call these G Y R B

ABCD will be one of these sequences

GYRB
GRBY
GBYR

RBGY BYGR YRGB

For initial playing i is unimportant if colours on coil are swapped as long as you know which wires go on which coil

eg YR GB, RY GB, YR BG and YR GB are all the same for 1st playing.

A or B to black will be 25 ohms.
C or D to white will be 25 ohms.

  • Look at motor part number and manufacturer

  • Tell us what they are

  • Locate a web based data sheet

  • Give us the address

  • From the data sheet determine the CORRECT voltage the stepper should run on.

  • Use the correct voltage

  • +ve = postitive = V+

  • -ve = ground

  • Connect white and black to v+

  • Ground A and B.
    You will have assigned CORRECT colours to A & B and C & D above.

THEN -

ROTATION CYCLE

  • Disconnect A, ground B
  • Disconnect C, ground D
  • Disconnect B, ground A
  • Disconnect D, ground C

Motor should have gone through one stepping cycle.
Repeat from "rotation cycle" as desired.
To reverse - swap A with B. Swap C with D

If motor does not move AND voltage is correct then motor is very probably broken.

If motor moves but oscillates to and fro over multiple cycles then swap mentions of A & B in instructions above and retry. (ir where it says A use B. Where it says B uses A).

BUT it is more likely that you are using a voltage that is far too small.

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