# 3D Printing > 3D Printer Parts, Filament & Materials >  Anyone recognize this motor?

## BLKKROW

There are no markings or words. Just a stepper motor with 6 pins. I need a replacement but I don't know what to buy?

Any help or links to a new one?

----------


## Geoff

Measure it, if it is 4cmx4cm, just buy a standard NEMA17 to replace it. I sell them on Ebay for about $20

Finding the pins are very easy...  Just use a multimeter.

 Use the circuit tester beep.. Connect two of the 6 wires to the multimeter and turn the motor by hand - if you don't get a beep or circuit closed, then switch to another wire.. 

You are looking for the 2 pairs you need, 1A,1B - 2A,2B.  Keep trying pairs until you get the beep.

----------


## BLKKROW

42.28mm X 42.28mm X 34mm is what my calipers are giving me.

34mm is the length.

So will yours work?

----------


## Geoff

Yes but I only ship within Australia sorry, too expensive otherwise. 

These guys ship world wide tho, they have good feedback

http://www.ebay.com.au/itm/NEMA-17-S...item19e282efb8

----------


## BLKKROW

Well Geoff,

I got a replacement motor, but when I place my printer into Jog Mode and try to utilize the new motor it isn't working correctly.

Instead of the armature spinning in one direction, it just spins one direction then the other direction like a jiggle.

Any suggestions, I really need my printer and am getting really frustrated.

----------


## Mjolinor

Are there six wires in your original connector wire?

Are there six connections on your new motor?

----------


## BLKKROW

> Are there six wires in your original connector wire?
> 
> Are there six connections on your new motor?


Yes and Yes.

I presume the wiring is the same. Also spinning the armature on the new motor is fantastic nice and smooth. While the old motor is very difficult to turn by hand and the bearings on the inside spin freely so it may have something to do with the magnets?

After playing with the old motor it is spinning more freely now.

----------


## Mjolinor

you need to measure the resistance between the connections on the new motor.

http://www.talkingelectronics.com/pr...pperMotor.html

Just down that page a short way is an explanation of the difference between 4, 6 and 8 wire steppers. You can see that centre to outside will be half the resistance of outside to outside. Using that you can draw the wiring of the pins for your new motor. Repeat for the old motor and see if they are the same.

----------


## BLKKROW

> you need to measure the resistance between the connections on the new motor.
> 
> http://www.talkingelectronics.com/pr...pperMotor.html
> 
> Just down that page a short way is an explanation of the difference between 4, 6 and 8 wire steppers. You can see that centre to outside will be half the resistance of outside to outside. Using that you can draw the wiring of the pins for your new motor. Repeat for the old motor and see if they are the same.


Thank you! Time to break out my multimeter

----------


## BLKKROW

> Measure it, if it is 4cmx4cm, just buy a standard NEMA17 to replace it. I sell them on Ebay for about $20
> 
> Finding the pins are very easy...  Just use a multimeter.
> 
>  Use the circuit tester beep.. Connect two of the 6 wires to the multimeter and turn the motor by hand - if you don't get a beep or circuit closed, then switch to another wire.. 
> 
> You are looking for the 2 pairs you need, 1A,1B - 2A,2B.  Keep trying pairs until you get the beep.


I appologize for the late reply, my friend had my multimeter and recently purchased me another one to use.

When you say Circuit tester, the functions I am using is the continuity test.

Is this correct? Also I do not know what you mean by the 2 pairs, 1A, 1B -2A,2B. Can you explain further?

----------


## Mjolinor

Your motor has 2 coils inside, these are called (for example) coils 1 and coil 2. Each coil has 2 ends, these are called A and B so you have 4 connections, call them 1A 1B 2A 2B. That is the standard notation that everyone uses for a 4 wire motor.

It is explained in the link I posted.

You normally want resistance test not continuity but it does depend on your meter and exactly what you are trying to do.

----------


## BLKKROW

> Your motor has 2 coils inside, these are called (for example) coils 1 and coil 2. Each coil has 2 ends, these are called A and B so you have 4 connections, call them 1A 1B 2A 2B. That is the standard notation that everyone uses for a 4 wire motor.
> 
> It is explained in the link I posted.
> 
> You normally want resistance test not continuity but it does depend on your meter and exactly what you are trying to do.


Well I have found the two pairs of pins that show resistance, on my new motor. I will pull off my old motor and check that also.

My main question is the wiring. Do the two pairs or A and B have to be wired to a matching A and B from the old motor? Like A to A and B to B or can I swap them around?

----------


## Mjolinor

> Well I have found the two pairs of pins that show resistance, on my new motor. I will pull off my old motor and check that also.
> 
> My main question is the wiring. Do the two pairs or A and B have to be wired to a matching A and B from the old motor? Like A to A and B to B or can I swap them around?


If A and B are swapped on one coil then the motor will run the other way round. If they are swapped on both coils it will be OK. If you do not wire correctly and swap a terminal from coils one and two then the motor will not do anything.

----------


## BLKKROW

> If A and B are swapped on one coil then the motor will run the other way round. If they are swapped on both coils it will be OK. If you do not wire correctly and swap a terminal from coils one and two then the motor will not do anything.


Then is there a way to differentiate A from B?

----------


## Mjolinor

> Then is there a way to differentiate A from B?


It is not possible without some serious testing gear and it is not necessary, if it rotates the wrong way then reverse one pair.

----------


## BLKKROW

> It is not possible without some serious testing gear and it is not necessary, if it rotates the wrong way then reverse one pair.


Cool thank you!

----------


## BLKKROW

> It is not possible without some serious testing gear and it is not necessary, if it rotates the wrong way then reverse one pair.


Thank you thank you thank you!

After some quick work the new motor is in and working perfectly!

----------


## BLKKROW

So I installed the new motor and it is extremely loud and it runs really warm. So warm that it melted some of the nylon standoffs.

I lubed all the guide rods and tightened all my screws and am still getting a really loud motor/printer. Now I am looking to purchase another motor and found the following website:

http://www.omc-stepperonline.com/ste...rs-c-1_21.html

Am I looking to purchase a unipolar or bipolar motor?

----------


## GOC

-    If your motors getting toasty you may not have the right voltage stepper. I would test the motor driver with your multimeter and see what the driving voltage is and make sure the motor is rated to handle it.

Examples of different Nema 17 Steppers:

*3.4V Stepper*

*12V Stepper*

*24V Stepper*

_*PS:_ These are just examples of the different Nema 17 style motors, I have no experiences with these sellers.

----------


## BLKKROW

> -    If your motors getting toasty you may not have the right voltage stepper. I would test the motor driver with your multimeter and see what the driving voltage is and make sure the motor is rated to handle it.
> 
> Examples of different Nema 17 Steppers:
> 
> *3.4V Stepper*
> 
> *12V Stepper*
> 
> *24V Stepper*
> ...


How would you measure the voltage?

----------


## GOC

> How would you measure the voltage?


-    Measuring the voltage will vary depending on what type of board you have and how the driver input power is sent. The place you need to measure the voltage is at the "Driver Power" source; see image below for an example.

----------


## BLKKROW

> -    Measuring the voltage will vary depending on what type of board you have and how the driver input power is sent. The place you need to measure the voltage is at the "Driver Power" source; see image below for an example.


Thank you for the information! Do I have to measure the voltage while the motor is running? Or can I just have the machine on?

----------


## GOC

> Thank you for the information! Do I have to measure the voltage while the motor is running? Or can I just have the machine on?


Just needs to be on.

----------


## BLKKROW

> Just needs to be on.


I finally had time to open up my machine and found the following:



I presume to measure the voltage I use the GND and VMOT, is this what you would do?

Edit: When I measure the voltage through the above mentioned terminals, I am reading 24 volts. This doesn't sound right.

----------


## GOC

> ...
> I use the GND and VMOT, is this what you would do?
> ...


-    Yes, that is correct.




> ...
> I am reading 24 volts.
> ...


-    Yes, this is also correct. Seems like your running a 24v setup, which is very nice because they tend to draw less amps. That will however make a lower voltage motor get real toasty for sure. You'll need a motor in like *THIS* (_I don't know this seller; just using as reference_).

_Edit:_ Make sure to use the GND that's next to the VMOT when measuring, not the one at the top.

----------


## BLKKROW

> -    Yes, that is correct.
> 
> 
> 
> -    Yes, this is also correct. Seems like your running a 24v setup, which is very nice because they tend to draw less amps. That will however make a lower voltage motor get real toasty for sure. You'll need a motor in like *THIS* (_I don't know this seller; just using as reference_).
> 
> _Edit:_ Make sure to use the GND that's next to the VMOT when measuring, not the one at the top.


Would that be Nema 17 or 16?

I am just trying to find one from a reliable retailer.

Edit: Sorry I see it listed as Nema 17, I just cannot find a 24v stepper motor anywhere but eBay.com

----------


## GOC

> Would that be Nema 17 or 16?...


-    I'm not certain of that, I think Geoff might have more experience for identifying the motor type. I'm more of a circuit board expert.




> ...
> Measure it, if it is 4cmx4cm, just buy a standard NEMA17...

----------


## Mjolinor

Working voltage on stepper motors in the days of modern electronics is meaningless. The driver circuitry is a current limiting device so no matter what voltage the stepper is rated at it is the current that is controlled.

If your driver circuitry cannot achieve the maximum rated current of the motor then the motor will not produce maximum torque.

----------


## GOC

> Working voltage on stepper motors in the days of modern electronics is meaningless...


-    I don't know about that, from my knowledge of motors the winding is specific to the voltage required for optimal operation (_hence the motor rating_). I gained my some of my stepper knowledge from *THIS PDF* & *THIS PDF*. High voltage motor winding's tend to give more running and holding torque.

----------


## Mjolinor

> -    I don't know about that, from my knowledge of motors the winding is specific to the voltage required for optimal operation (_hence the motor rating_). I gained my some of my stepper knowledge from *THIS PDF* & *THIS PDF*. High voltage motor winding's tend to give more running and holding torque.


Which is what I said worded in a different way.

If you have 2 stepper motors, one being 12 volt and one being 24 volt but both rated at 2 amps then the power output, at maximum volt and current, of the 24 volt one will be twice the power output of the 12 volt one (assuming the same efficiency).

If you run them from 12 volt then the power output from both motors will be the same because it is the current that is regulated, not the voltage.

In reality the 24 volt one will produce slightly less power than the 12 volt one when running from 12 volt because the magnetising power needed on the 24 volt one will be higher than the 12 volt one but you will not notice a difference in real usage.

In the environment of 3d printers you are unlikely to come anywhere near needing the maximum of any stepper motor no matter what voltage or current it is rated for.

The stepper driver limits the current, it doesn't care what voltage you apply as long as you do not exceed the maximum of the driver circuitry which is around 35 volts for the chip that is most commonly used. 

If you set the current to some value less than the V/R value of the system then all that will happen is that the stepper driver will drop the voltage applied to the stepper motor because the stepper motor must obey Ohms law whereas the stepper driver does not obey Ohms law. This is assuming that we are not in the realms of the dynamic impedance of the motor affecting the current flow which we will almost certainly never be with the speeds used in these types of machine.

----------


## GOC

> Which is what I said worded in a different way.


-    I'm sorry about that, I misinterpreted your reply. I though it was implying that you could run 24v across a lower voltage stepper motor (_ie: 5v) without any efficiency reduction._

----------


## Mjolinor

> -    I'm sorry about that, I misinterpreted your reply. I though it was implying that you could run 24v across a lower voltage stepper motor (_ie: 5v_) without any efficiency reduction.


You can use a 24 volt supply with a 5 volt stepper without any damage at all. This is achieved by regulating the current with the stepper driver adjustment to a value that the 5 volt motor can handle, the stepper driver will regulate the voltage to 5 volts automatically, that is the whole reason to use current controlled drivers.

----------


## GOC

Good info, I will have to do some playing around with my multimeter. I guess I still got some learning to do.

----------


## Mjolinor

Assuming the correct motor type, eg: 6 wire, 4 wire, 8 wire then the questions in the correct order are:

Is the motor the right size physically?
Does the motor have suitable torque?
Is the specified current of the motor within the adjustment range of the stepper driver?
Is the specified voltage of the motor lower than or equal to my power supply?

----------


## BLKKROW

> Assuming the correct motor type, eg: 6 wire, 4 wire, 8 wire then the questions in the correct order are:
> 
> Is the motor the right size physically?
> Does the motor have suitable torque?
> Is the specified current of the motor within the adjustment range of the stepper driver?
> Is the specified voltage of the motor lower than or equal to my power supply?


So where should I begin?

My motor is the right size, but I have no info on the previous motor.

Would measuring the current while the machine is on, help? If so would you place the multimeter in the same place to check voltage?

After some research I purchased the motor (12V 0.4A) from the link below: 

http://www.ebay.com/itm/331084351443...%3AMEBIDX%3AIT

So after reading the responses above and trying to remember my electricity and magnetism physics. It sounds like them motor I purchased has low torque and draws low amps, compared to what was originally in the machine?

After more research I have found that the board to control everything is based on the Makerbot MightyBoard:

http://www.thingiverse.com/thing:16058/#files

----------


## oklok

looks like Steppar 42!?

----------


## BLKKROW

I do believe its a Nema 17 motor.

Any input on what I should purchase? I feel like the current motor I have has a low amperage, compared to what the stepper drive is delivering. So it is then overheating.

----------


## Mjolinor

Adjust the current

On the mighty board you can do this in software.

In your Gcode you should have a line like this:
G130 X0 Y0 A0 B0; set stepper motor vref to lower value while heating

Later in your Gcode you should have this:
G130 X127 Y127 A127 B127; set stepper motor vref to defaults

The first line turns off the steppers and the second line turns them on again.

If you change the second occurrence of the line to:
G130 X64 Y127 A127 B127

it will drop the current for the X stepper to about half what it was.

The lower you make it the lower the current will be but also you will lose power so probably you cannot print as fast as you could. Try lots fof increasing values until you get a reasonable speed without skipping steps. Once you get there make sure the stepper is not getting too hot.

----------


## Mjolinor

Those lines should be in your start.gcode so you can save the value you decide on to make it permanent.

----------


## BLKKROW

This is the beginning of the Gcode that I have. I see the first option you mentioned but not the second. Where should I add it?

Never mind I see it now! Right now its set at Y127. Its the Y motor that is over heating. So should I lower it to Y100?

----------


## Mjolinor

> M103 ;disable RPM M73 P0 ;enable build progress 
> G21 ;set units to mm G90 ;set positioning to absolute 
> (**** begin homing ****) 
> G162 X Y F2500 ;home XY axes maximum 
> G161 Z F1100 ;home Z axis minimum 
> G92 Z-5 ;set Z to -5 
> G1 Z0.0 ;move Z to "0" 
> G161 Z F100 ;home Z axis minimum 
> M132 X Y Z A B ;Recall stored home offsets for XYZAB axis 
> ...


Here it is



> G130 X127 Y127 Z40 A127 B127 ;Set Stepper motor Vref to defaults 
> 
> 
> 
> M108 R3.0 T0 
> G0 X-141 Y-74 ;Position Nozzle 
> G0 Z1 ;Move above plate 
> G1 Z0.3 ;Position Height M108 R5.0 ;Set Extruder Speed 
> M101 ;Start Extruder 
> ...

----------


## Mjolinor

Yes, try 100. 

You will not break anything it will just not move correctly or may skip steps if you go to low, if you are too high then it will still overheat.

----------


## BLKKROW

Thank you for the help! 

I will try that today and see what I can do.

----------

