Stepper motor help needed

[zap]

I have a Nidec 24v stepper motor that I want to try and use for a project and 24v would be perfect.  It was out of a laser printer and I still have most of it's gearing and I'll need to be using at least some of that.

The stepper is connected to a pc board and it appears to be intact.

One of the problems is that, what I assume is the controller ic has a heat sink that was screwed to it from the bottom of the ic before it was soldered to the pc board and the screw heads are now "hidden" for lack of a better word.  I can't get at the screws to remove the heat sink to read the part number without unsoldering the ic... I'd rather not have to do that.

There is a 6 pin connector on the board, it is the only connection on the board, and the pin outs are labeled:

6. -CW/CCW
   
5. -NC
   
4. -GND
   
3. -+24V
   
2. -ON/OFF
   
1. -LOCK
   
   

Without knowing the ic's part number, does the ic use the 24v to run motor AND itself or is it more likely the chip requires a 5v supply and if so does it use the same GND for (-)negative and the 5v(+)positive would be hooked momentarily to the control pins?

I would need to run the motor in both directions with a rocker switch but would only need a few seconds of run time when I need it... i.e. not continuous.

Also, I figure the CW/CCW is clockwise/counterclockwise but what determines the direction?  A momentary signal?

Does the NC stand for normally closed and if so, what is it that's normally closed?

What is the ON/OFF pin?

What is the LOCK pin?

Thanks for any help.  It's been decades since I've messed with any ic other than a 555.

[TomW]

zap;

Do not mistake me for an expert but...

"NC" can mean "No Connection" also.

"on/off" could be "power" ie the +5V for the logic circuit.

"lock" could be an interlock that prevents movement if an access panel is open.Might need either a logic 0 or a 1 to operate the motor hard to know easy to test.

All guesses.

Been awhile since I reverse engineered anything but used to do it a fair bit. Lots of fun with the occasional magic smoke release but that never stopped me

Tom

[zap]

Thanks Tom

Even though I've seen "No Connection" before that never dawned on me.

I guess I'll just have to play with it and risk the magic smoke.

I now wish I'd kept more of the bits from the printer.

[ruddycrazy]

G'day Zap,

           I'm currently on building myself a small cnc using steppers so I just might know a thing about them or 3. OKAY how many wires are there coming out of the stepper, this will determine if it is unipolar or bipolar. Often I found steppers out of printers were generally too small to use but I did find a decent one recently. The spec's are 3.6 volts 1.4 amps and I can honestly say I've never seen a 24 volt stepper before. Generally the pcb boards out of printers will be a very hard job to get working out of the printer so I've always found making my own stepper drives works the best.

A 4 wire stepper is a bipolar

A 6 wire stepper is unipolar but by deleting the power lines it can be used as a stepper.

A 8 wire stepper can either be bipolar or unipolar depending on the wire connection.

I did last year have the opportunity to get some 5 phase steppers (10 wires) but declined as controlling them would be a nightmare.

Cheers Bryan

[zap]

Thanks for the reply Bryan.

I did a little deeper googling yesterday and found this is probably just a brushless motor, not a stepper... sorry all.

I'm too lazy to hunt down the camera but here's a link to something similar.

http://www.nidec.com/admtypem/40m58m.pdf

Mine is the 45m (45M2880020) series but I think mine is maybe older since mine only has a 6 pinout and the motors shown in the link have a 9 pinout.  Mine only has a few SMD components on the "shaft" side, the driver is on the other side.

I messed around with it a little yesterday but I could never get it to work.  I was using the GND pin for the 24v(-) and for the logic ground since mine has no pin labeled "logic".  I may try messing with it some more but more than likely will head in a different direction.

I found a NiCd battery powered drill in the trash and will try rewinding the motor for 24v.  The drill has decent metal gears and would probably work well for what I need.

 

[szmeu]

I know this is an old thread but thought might be useful for other people with the same dilemma and searching for answers, I have the same motor with on the same PCB with the driver, without the proper information at hand I decided to desolder the ic and took a peak, the driver ic is LB1927 - it's a driver for three-phase brushless motor, I scavenged mine from a Brother - HL 1230 printer...

managed to start the motor the following way:

6 - CW/CCW - this will give the rotation direction (let it float or to the ground to revers direction)
5 - NC - not connected
4 - GND - ground
3 - +24V - positive voltage (between 10 to 30V)
2 - ON/OFF - this will start the motor (to start the motor this pin must be sinked to ground)
1 - LOCK - I don't use this one, so I let it float, did not understand exactly what it does from the datasheet, I guess it's a signalling pin (pin 15 - LD - Speed lock detection pin).

Now I have to find a way to control rotational speed, I need it to step slower to use it to drive the fusser for a PCB toner transfer method machine I'm working on. I studied the datasheet but is not clear yet how to modify the speed (the current schematic uses an crystal oscillator). If anyone has an simple idea after studying the datasheet would be nice to mention it here. Thanks

[ruddycrazy]

Hi szmeu,
             Welcome to the forum mate, I had a look at the datasheet you provided and on reading ( 5. Reference clock ) is the way to adjust the speed. Now as your going to use this as a toner transfer drive motor you shouldn't need variable speed but a slow constant speed with forward/reverse. Now it does show 2 ways to do it via the oscillator or external. Note the frequency is in Mhz so personally i'd make a the oscillator circuit and put a couple of machine pin headers in for it. Then you can change them out with different values to get the required speed. Another way would be just gear down the drive to increase torque and using the right ratio will get you the required speed.

Cheers Bryan

[szmeu]

Hi Bryan,
Thanks for the swift reply, I did not want to mess with the mechanical part so I decided to do it from the circuit, for now I just exchanged the crystal on the pcb with a 4Mhz, I don't know the value for the one originally installed (it is not clearly marked) but it was a higher freq because now the rotational speed is almost ok, I'll have to try and see if this speed will do the job. I'll order some 1 and 2 Mhz crystals just to be on the safe side an will further reduce oscillation frequency if needed.
With the 4Mhz crystal torque is plenty and hope will perform well for the required job.

[ruddycrazy]

Hi Szmeu,
              Great news that just changing the crystal does the job. Eh mate how about starting your own diary thread with this toner transfer project your doing as when I get time (next joke) I'll get back onto my toner transfer project which is an old fuser head out of a digital brand laser printer. Using a 89 volt DC power supply it only takes about 5 minutes to get the heating roller upto 200C but the chip I used for the stepper motor couldn't handle the current so that where the project stalled.

            Eh ya never know posting projects like this might even get some of the members out of the dark ages and realize just how easy it is to make circuitboards.

Cheers Bryan

[szmeu]

Good idea, I intend to do just that, I'm documenting this work so that I can make a tutorial, this is pure pleasure and nice way to learn new things, found some good info about comparators (using lm339) this will be used to control the roller heat and some led displaying status of the toner-to-pcb-transfer machine. Hope I was not to off topic, I'll be back soon to start a thread on this modification just need to sort out a few things.
See ya soon,
szmeu