Bipolar Stepper motor driver

[zohaib]

Hello forum

How can i drive my bipolar stepper motor (6 wires, 3.2Volt, 0.8 Ampere) using uln2003, Maximum output current for uln2003 is 600mA. Please Help

Thanks.

 

[FvM]

A bipolar stepper motor usually has 4 rather than 6 wires. You should clarify the actual windings connection first, or tell the motor type.

If it's actually bipolar, it can't be driven by unipolar drivers like ULN2803. For a two-phase bipolar stepper, consider two H-bridges https://en.wikipedia.org/wiki/H-bridge

 

[zohaib]

Thanks FvM,
Basically Motor has 6 wires where two center tap wires of the coils are connected to 5V and remaining 4 wires are grounded (For testing) one by one to move motor one step . Now i have to ground these wires through some driver circuitry which can accept more than 0.8 Ampere and can operate on logic from 8051 micro.

 

[FvM]

Basically Motor has 6 wires where two center tap wires of the coils are connected to 5V and remaining 4 wires are grounded (For testing) one by one to move motor one step . Now i have to ground these wires through some driver circuitry which can accept more than 0.8 Ampere and can operate on logic from 8051 micro.

In other words, your stepper motor is unipolar, not bipolar.

Using 4 individual MOSFETs is the most simple way to drive the motor with currents of 0.8 A.

 

[zohaib]

some one told me if i reverse the switching i can get reverse rotation as well.. anyway can i use TIP120 as it also has built in back emf protection...

 

[engineerpervez1]

Bipolar motor have 6 wires or you can say Two separate center tapped winding.
It has a unique pattern two drive output. as two friends are walking together in 4 square boundary :lol:
I mean to say.

1100 1st step
0110 2nd step
0011 3rd step
1001 4th step (here they separate for some time)

1100 (No problem here they meet again :lol: again first step.this is all for full step
old sylosyn motors had 200 step /rev

don't forget to insert a low value of resistor at the both center wires for current limit
don't ask me me for 1/2 step :-(

 

[zohaib]

thanks pervez,
it means i can't obtain bipolar mechanism with connecting both center tap wires?

 

[FvM]

it means i can't obtain bipolar mechanism with connecting both center tap wires?

I guess you are misunderstanding the term "bipolar". You can in fact drive an unipolar motor by a bipolar driver, but then you won't connect the center taps,

some one told me if i reverse the switching i can get reverse rotation as well

Yes by reversing the switch pulse sequence. It hasn't to do with bipolar versus unipolar drive.

 

[zohaib]

Thanks FvM,
I think i need some more theory work to do, will get back to you soon, thanks for support.

 

[engineerpervez1]

It is not so difficult If you have some micro controller knowledge you can manage it. Long ago I have design a complete circuit and software and put on web (geocities free web) it lost by the time as geocities has stopped free domain service.
which city you belongs.
watch my website if u r interested learning micro controller.
www.micromultitasking.com.
some day i will put this circuit again.

- - - Updated - - -

sorry I have mistaken or you were misunderstood already 6 wire motors are unipoler motors.see the nice description for more detail.
https://www.stepperworld.com/Tutorials/pgUnipolarTutorial.htm
what all I told you it is about unipoler motors.
You still have to find out it is bi-poler or unipoler.It is very easy to find out by multimeter.