# 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?

active| newest | oldestI picked up a stepper motor online which carries a nameplate with spec

42HS40-0804A05-D25

I want to know the details of this spec.

Xavier

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:

https://www.instructables.com/id/Control-your-motors-with-L293D-and-Arduino/

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

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 ?

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.

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.

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.

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