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#3994 - 09/04/01 05:23 PM Stepper motors - how to make them operate
Anonymous
Unregistered

I took some of my old printers and a scanner apart to expand my hardware inventory. I found several stepper motors.

There are things I want to rotate, and even partially rotate. If I hook up one of these stepper motors to power, will it just spin? Do these stepper motors require a computer to tell them to work? If they turn a partial rotation and stop, how is that accomplished?

Roger
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#3995 - 09/04/01 07:02 PM Re: Stepper motors - how to make them operate
Anonymous
Unregistered

Links for those interested in running a salvaged stepper motor:


[*]Drivers

Dual Full Bridge Driver L298: http://www.alltronics.com/download/1773.pdf
Push-Pull Four Channel Driver With Diodes L293D http://www.alltronics.com/download/1330.pdf
Push-Pull Four Channel Drivers L293B, L293E http://www.st.com/stonline/books/pdf/docs/1328.pdf
Push-Pull Four Channel/Dual H-Bridge Driver L293C: http://www.st.com/stonline/books/pdf/docs/1329.pdf
Push-Pull Four Channel Driver With Diodes L293 L293DD: http://www.st.com/stonline/books/pdf/docs/1330.pdf
Dual Full Bridge Driver L298: http://www.st.com/stonline/books/pdf/docs/1329.pdf
Stepper Motor Driver Considerations Common Problems and Solutions: http://www.st.com/stonline/books/pdf/docs/1675.pdf
Stepper Motor Driving: http://www.st.com/stonline/books/pdf/docs/1679.pdf
Stepper Motor Driving: http://www.st.com/stonline/books/pdf/docs/1679.pdf
Applications of monolithic bridge drivers: http://www.st.com/stonline/books/pdf/docs/1681.pdf



[*]Controllers

Bipolar Stepper Motor Control: http://www.st.com/stonline/books/pdf/docs/1700.pdf
L297 stepper motor controller: http://www.st.com/stonline/books/pdf/docs/1734.pdf
Stepper Motor Controllers L297/D: http://www.alltronics.com/download/1334.pdf
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#3996 - 09/06/01 05:18 PM Re: Stepper motors - how to make them operate
bordew Offline
Member
Registered: 08/27/01
Posts: 142
Loc: Vienna,Ohio, USA
Quote:
Originally posted by jairtime@earthlink.net:
I took some of my old printers and a scanner apart to expand my hardware inventory. I found several stepper motors.

There are things I want to rotate, and even partially rotate. If I hook up one of these stepper motors to power, will it just spin? Do these stepper motors require a computer to tell them to work? If they turn a partial rotation and stop, how is that accomplished?

Roger


A stepper motor is a device whose input is an electrical pulse and whose output is the rotation of its shaft. For each pulse the motor recceives, its shaft rotates through a fixed precise angle. Depending on the pattern of pulses applied, the stepper can be used to control the position and/or velocity of a load accurately.
Some advantages are the error is the single step error(usually less than 5% of one step and therefore noncumulative, as opposed to a DC controller which has armature feedback sent to a summing network to help compensate for load changes)
The motor is controlled by drive circuitry and a dc power supply, the circuitry dictates the motors response.
Radio Shack has 555 timers and playing around with the outputs can be set up to control these motors nicely. Also J-K flip-flops work quite nice too.
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#3997 - 09/07/01 10:13 AM Re: Stepper motors - how to make them operate
Anonymous
Unregistered

So am I able to hook the motor up to DC power and a switch, turn it on an run it? Does such a motor require the circuitry you describe in order to run at all?

Thanks for your help!!!

Roger
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#3998 - 09/07/01 05:37 PM Re: Stepper motors - how to make them operate
bordew Offline
Member
Registered: 08/27/01
Posts: 142
Loc: Vienna,Ohio, USA
Quote:
Originally posted by jairtime@earthlink.net:
So am I able to hook the motor up to DC power and a switch, turn it on an run it? Does such a motor require the circuitry you describe in order to run at all?

Thanks for your help!!!

Roger


On a stepper motor, they frequently come with 8 poles whose polarities are changed by switching. the rotor magnetism can be generated by external excitation or a permanent magnet.
A 4 stator winding motor has 8 poles possibly 5 leads coming out of the motor. In order to hook this up properly you will need a wiring diagram because the stator fields are paired these have to recieve a pulse train from the timers. a small dc supply will also be needed.
As stated in a 4 winding stator there are paired fields call them A and A', the second pair B and B'.
A and A' are internally tied together as are B and B'. The center point of each pair of coils is tappen and center point ofBB' is tied to center point AA' a common lead is brought out to make a total of 5 you will need some type of continuity tester to locate the winding leads. the common lead, the center tap receives the pure DC for Excitation, and a series dropping resistor must be used to limit the current to the fields a small pot say 0-5k would work fine.
the other two field leads, once isolated need to recieve the pulse train, the reference for all this can be an output from a 555 timer set up as a one-shot to feed a pair of J-k flip-flops, J-K because you get two outputs from them that is output Q and Not-Q in other words what it is actually a 1 and a 0 when Q goes high Not-Q goes low, all these parts can be obtained from Radio Shack. The inputs J and K must be held high to a 5 volt source and the clocks on the JK receices the input from the 555 timer. Also RS has some literature on Digital circuits and different flip-flops and how they work.
Also the outputs from the flip-flops must be sinked so as not to swamp out the output, this is accomplished with a transistor at each output of the FF ie,Q and Not-Q will recieve a xtr the collectors of the transistors will be tied to the input of the stepper fields.
Give it a try , be creative.
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#3999 - 09/08/01 12:44 AM Re: Stepper motors - how to make them operate
Anonymous
Unregistered

Hell, if I'd known it was that simple, I'd have had one of my kids wire it up!

Just kidding! Seriously, electrical is like heiroglyphics to me, I'm a woodworking and welding type guy, but I wonder if I could just re-use the circuitry and resistor(s) from the printer/scanners I took the stepper motors from. I guess it should be there, right? If not, Radio Shack?

Thanks again for the help!

Roger
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#4000 - 09/08/01 05:50 AM Re: Stepper motors - how to make them operate
Bill Addiss Offline
Member
Registered: 10/07/00
Posts: 3875
Loc: NY, USA
Roger,

Just wanted to say, Welcome to the Forum. I was looking at your profile and noticed that the website link doesn't work. You have to put http:// in front of the www or it doesn't work from within this forum. I think that others may find it very interesting.

http://www.johnnyairtime.com/


You've got a pretty intense Job and Hobby there I'd say!

Bill

[This message has been edited by Bill Addiss (edited 09-08-2001).]
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#4001 - 09/08/01 10:51 AM Re: Stepper motors - how to make them operate
Anonymous
Unregistered

Thanks, Bill! I'm glad this forum is here!

I edited my profile, hopefully it will work now!

Roger
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#4002 - 09/08/01 11:30 AM Re: Stepper motors - how to make them operate
bordew Offline
Member
Registered: 08/27/01
Posts: 142
Loc: Vienna,Ohio, USA
Quote:
Originally posted by jairtime@earthlink.net:
Hell, if I'd known it was that simple, I'd have had one of my kids wire it up!

Just kidding! Seriously, electrical is like heiroglyphics to me, I'm a woodworking and welding type guy, but I wonder if I could just re-use the circuitry and resistor(s) from the printer/scanners I took the stepper motors from. I guess it should be there, right? If not, Radio Shack?

Thanks again for the help!

Roger


Sure you can re-use the circuitry, but you still may have to provide a pulse, most digital circuits are 0-5volts and there is a limit before the electronics will self-dstruct. Cmos are a bit higher, but if it is not cmos it will be about 5 volts.
The driver circuit should still be ok, but you will have to look for the input section, if it came out of a printer the the signal source was probably the pc and the software that provided the info to the driver.
So as I said, good luck.
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#4003 - 09/08/01 04:09 PM Re: Stepper motors - how to make them operate
Anonymous
Unregistered

Thank you VERY MUCH! You've been very helpful. I can see that it's beyond my ability to create a working system with these stepper motors. I've got 5 of them, hopefully I'll be able to use them for something.

Take care!

Roger
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