[Ask]Driving Motor Stepper

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senoseno

Joined: 25 Sep 2006
Posts: 3

01 Sep 2008 11:43 driving motor voltage

Hi all,
Is it possible to drive the Sanyo Denki Stepper-Syn 103G771-0611 motor stepper with ULN2003?

james bond007

Joined: 19 Aug 2007
Posts: 24
Helped: 1

04 Sep 2008 1:16 sanyo denki 103g771

hi,
stepper motor is driven by supplying voltage to its coil in a particular sequence. ULN is simply a current regulator and it can supply the current required by the stepper motor (550mA). We use ULN only to provide the necessary current as this cant be supplied by the microcontroller(PIC, ATMEL, ATMEGA, etc.).
So as long as ur coding is correct ur motor will run. However you may have problems with the back emf of motor,,,for that you can use diodes for fast decay of current(this is the testing phase).

Sinisa

Joined: 03 Mar 2003
Posts: 337
Helped: 66

04 Sep 2008 3:46 step syn type 103g771-0611

Your driver looks like this:

[Ask]Driving Motor Stepper

You could use this driver to run motor in unipolar mode, but for this motor you need rating of couple of amps.

[Ask]Driving Motor Stepper

It is easy to build discrete driver as one in ULN2003 that would have sufficient rating. You connect midle terminals to appropriate positive voltage and remaining wires are fed to your driver output.

And one more thing: ULN2003 is NOT a current regulator.

FvM

Joined: 22 Jan 2008
Posts: 5160
Helped: 767
Location: Bochum, Germany

04 Sep 2008 8:28 103g771-0611 power supply

Quote:

Hi all,
Is it possible to drive the Sanyo Denki Stepper-Syn 103G771-0611 motor stepper with ULN2003?

It is not possible, if this specification, that I found for it would be correct: 2.46V/1.82A per winding (1.35 ohm)

ULN2003 cant' provide the current and is too slow for PWM constant current operation, that's obviously required with this motor.

Sinisa

Joined: 03 Mar 2003
Posts: 337
Helped: 66

04 Sep 2008 13:54 datasheet step syn sanyo denki

FvM wrote:

ULN2003 cant' provide the current and is too slow for PWM constant current operation, that's obviously required with this motor.

I would not agree that constant current is required. It is desired, as is for any stepper motor, but senoseno has first to learn simple full step unipolar driving of stepper before he could venture into constant current, microstepping and such. Most hobbyists chose stepper motor for simplicity anyway.

Senoseno, if you build discrete driver and power it with required voltage, you should be fine. Just read how stepper motor works in unipolar mode and create proper sequence.

james bond007

Joined: 19 Aug 2007
Posts: 24
Helped: 1

04 Sep 2008 22:30 stepping motor 103g771

hey senoseno i m sorry for saying ULN is a current regulator.
It is definitely not a current regulator.
I meant that its use in circuit is only to supply the required current to the stepper motor and it is a kind of current enhancer for the circuit.

Added after 5 minutes:

if what fvm said is true then i must say that it is hard to drive your motor through ULN,,,,for meeting current requirements you can use 4 ULN's connected in parallel,,,and your voltage requirement can b met by using a proper power supply.

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larsrc

Joined: 03 Jul 2009
Posts: 1
Location: Denmark

03 Jul 2009 20:44 datasheet 103g771

Sorry for resurrecting an old thread, but I'm having the damndest time finding any sort of data sheets for that particular stepper motor. I bought three of them used for use in a RepStrap, but they didn't come with a data sheet. Do you happen to have one you could mail me a copy of, Senoseno?

Thanks in advance,
-Lars Clausen