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Walt Langhans
10-02-2014, 8:20 PM
297743 297744

Hey guys.

My stepper motor died, and I'm not sure what kind I need to replace it.

It's the single shaft one and aside from the Chinese writing on it, it also has 57-H350C, and NO 1211

I'm looking at this motor
NEMA 23 Motor:

Specification:

Step angle: 1.8 deg
Step per revolution: 200
Phases: 2
No. wires: 8
Current: 4.0A
Holding Torque: 2.2 N.M (313oz*in)
Single shaft (dia./length): 8.0mm/19.6mm
Inductance: 1.8 mH
Phase resistance: 0.7 ohms
Detente torque: 700 gcm
Rotor Inertia: 480 g-cm2
Weight: 1.1KG (2.5lb)
Overall dimension (LxWxD):100.6mm x 56mmx56mm


and this one

Specification:


Step angle: 1.8 deg
Step per revolution: 200
Phases: 2
Single shaft, 5mm
No. wires: 4 or 6 central tag
Current: 2A
Holding Torque: 0.57 N.M (80oz*in)
Inductance: 3.6 mH
Phase resistance: 1.7 ohms
Detente torque: 200 gcm
Rotor Inertia: 82 g-cm2
Weight: 0.38KG (0.75lb)
Length: 48mm


But I'm not sure that either one of those is correct.

Also does anyone know how to remove the gear? It looks like is should have a screw in the top, but I can't find an Allen key that wanted to fit it, and on the nut (assuming that's what that is) on top of the gear

And now I'm finding that they are bipolar or unipolar, any one know the what that means and or the difference?

Anyone have any ideas / thoughts on this?

Keith Colson
10-02-2014, 11:06 PM
Hi Walt

I think you motor can be found here. Odds are it is bipolar with 4 wires used only. (6 wire works as a replacement, just don't use the center tap wires)

http://www.wantmotor.com/ProductsView.asp?id=160&pid=80

The key indicators you need to look at is: length mm is a good idea of torque so match that up. You can measure the phase resistance with a meter. Just remember to measure your meter leads first by touching them together and subtract that from your reading.

Then order it on ebay or alliexpress if you are not in a hurry. Your motor looks pretty common in type..

They normally have a set screw on the pulley. It will most likely be metric (as there is only one country still using non metric on that kinda stuff). We are only talking 30 bucks or so.

Those motors you have quote have extremely different dimensions in length so watch out for that.

Cheers
Keith

Scott Shepherd
10-03-2014, 8:00 AM
Sometimes those type pulleys are press fit. Just order a new pulley when you order the motor.

Rich Harman
10-03-2014, 4:07 PM
The stepper motor you pictured only has three wires visible. A four or eight wire stepper motor won't work unless you also replace the stepper driver.

Walt Langhans
10-03-2014, 4:26 PM
The stepper motor you pictured only has three wires visible. A four or eight wire stepper motor won't work unless you also replace the stepper driver.

Yeah that's what I'm learning, but I can't seem to find any in the US. Any idea where I can get one?

Rich Harman
10-03-2014, 4:37 PM
I don't know where to get one in the US. I think you'll have to get it from China. Are you certain that there is a problem with the motor? I have about 20 steppers that have been in regular use for years, never had one fail.

Bill George
10-03-2014, 4:43 PM
Yeah that's what I'm learning, but I can't seem to find any in the US. Any idea where I can get one?
My guess is they never brought the other wires out of the motor. What about getting one from the Mfg of the laser?

Walt Langhans
10-03-2014, 4:48 PM
I don't know where to get one in the US. I think you'll have to get it from China. Are you certain that there is a problem with the motor? I have about 20 steppers that have been in regular use for years, never had one fail.

Yeah positive it's the motor. From the laser control, I swapped the inputs to the stepper motor controller, nothing changed. Then I took the outputs of the stepper motor controllers and swapped the the stepper motors, nothing changed. I think what happened is that when they wired it at the factory they used a cloth cover over where they soldered, and then zip tied that cloth cover in place and it moved and allowed the bare wires to touch messing up the motor. I've also rewired the motor, and then re-installed it and the same issue happened.

Ross Moshinsky
10-03-2014, 5:19 PM
I'm not associated with this company but: http://www.automationtechnologiesinc.com/

They sell steppers for the CNC world and also dabble in laser engravers. My bet is they have something that will work for you. The other person to contact is Rabbit Laser. They probably have something that would work.

Keith Colson
10-04-2014, 5:21 AM
If it is 3 wires only then it is a three phase motor. Wantai have these (link below) motors which are compatible with 3 wires, see the diagram at the bottom. This would mean it is likely 1.2 degrees per step not 1.8 degrees per step, you could count this if you were patient and hand turned/clicked the motor (you can connected a couple of volts up if you need some mechanical resistance to click against.

http://www.wantmotor.com/ProductsView.asp?id=172&pid=80

Cheers
Keith

Bill George
10-04-2014, 8:55 AM
That website link comes up Blocked with my Virus protection software.

Keith Colson
10-04-2014, 9:08 PM
Hi Bill

If you test that page with https://www.virustotal.com/en/ it comes up clean. The biggest web browsing risk is generally using internet explorer. I have purchased many of those motors for 3d printers and robots etc with no problems. What browser and virus software are you using?

Cheers
Keith