How can I use a stepper motor that has no markings on it? (voltage, amps, rotation degrees) Just model numbers

I pulled 2 stepper motors out of a old printer. They look the same but there are no markings on them. Only one red and 3 white wires. I don't have them with me this week, but how could I test them over the weekend?

Picture of How can I use a stepper motor that has no markings on it? (voltage, amps, rotation degrees) Just model numbers
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XavierJ21 month ago

I picked up a stepper motor online which carries a nameplate with spec


I want to know the details of this spec.


rojecas2 months ago

Hi, you need a H-Bridge to control this kind of motors (bipolar ones), you can find several H-Bridge controllers for motors or inductive loads, a well known and documented is LC293D.
Yo can find an instructable with the required information here:

I don't know if this information is useful now, because are an old post. but surely for any other it will be.

bmn24 months ago

thank you for everyone who can help us

i have this 2 stepper motor EM-462 and EM-463 from an old printer, i ask if i can use it for a cnc arduino and what driver circuit can i use ?

_tika_2 years ago
These two motors come from an Epson 40 series. Motoring supply on these is 36V.

Both are bipolar stepper motors.

EM-462 is the carriage motor, EM-463 the paper feed motor.

They are driven by a custom Allegro chip, but these chips usually put out 1A max.

The power rating on the printer I have is 48W, so when both of them are on, they can't be drawing more than 1.2A combined. The driver uses PWM to limit the current.
mauad5 years ago
It is an old thread, but as I'm sure there are plenty of EM-462/3 units dusting on the shelves, I will post some info.

The measures are:

EM-462 Bipolar Stepper
Coil resistance: 9.2 Ohms
Coil wire diameter: 0.28 +/- 0.02 mm

EM-463 Bipolar Stepper
Coil resistance: 6.1 Ohms
Coil wire diameter: 0.28 +/- 0.02 mm

Using alexander.m's prescription (scroll to find the post), and using 0.26 mm as the reference diameter, one have 0.26 mm = 0.010 in, multiplied by 100 will give exactly 1.0 A as the current rating.

As soon as I drive them, I will post some results.
piratus mauad4 years ago
nice !! can you help me with his ; i wanna make them run with pic 16f84 , can you help me with this ?! thanks !!!!
tiar6 years ago
wiring diagram and driver motor for atmega 8535, please your send to my email?????
tiar6 years ago
mau tanya untuk diagram wiring ke atmega 8535 dan skalian driver motornya ada ndak? klo ada tolong kirim ke email saya ya tolooooong banget.
alexander.m6 years ago
First you need to know how to weir it, for instruction on that go to http://www.piclist.com/techref/io/stepper/wires.htm
To find the rated amperage you would need to take it apart then use a micrometer or Caliper to find the coil weir diameter (note: a ruler is not accurate enough) once you have the weir diameter change the measurement to inches in Decimal Value then multiply it by 100 then you have the amp rating. To find the voltage you need a ohm meter to find the ohm value then multiply ohms by the amps to find the volts rating. to find the rotation degrees then you need a controller to test this.
Rob K (author)  alexander.m6 years ago
I should have payed more attention to the steeper motors when I took them out.

The info on them in is the picture.

I cant find much info on line for the EM-463, but for the EM-462 all I have found out was that it is a Stepper motor for Epson 4-Wire Two 9-Ohm Coils on ribbon cable
Rob K (author)  alexander.m6 years ago
Thanks for the info. I look more at the stepper motors this weekend and see what I can find. From what I remember there was a metal mounting plate spot welded over where the stepper motor info would go.