How to Select a Disc Magnet Motor

Selection Criteria

P - Portescap Disc Magnet motor
X- Additional code; if P meaning Hall sensors integrated.

Motor diameter

The motor diameter (sometimes refered to as frame size) is the diameter to the nearest mm of the motor casing. Matching the motor diameter to the available space in the application is typically the best place to start when sizing a DMM. In general, larger frame size motors deliver more torque. Motor diameter ranges from 10 mm to 74 mm.


Ranges from 16.4 mm to 56 mm.

Motor version

If 2: motor recommended for both full and half step mode.
If 0: motor recommeded for microstepping (less than 5% third harmonic and low detent torque).

Number of rotor pole pairs

This determines the step angle. Step angles available are 3.6°, 6°, 7.5°, 9°, and 15°.

Number of terminal wires

4 means two phases, 1 coil per phase.
8 means two phases, 2 coils per phase.
This allows to have coils connected in series or parallel, or to drive motor in unipolar.

Resistance per winding

Current, voltage and driver type used will help selecting coil.

Internal motor execution code

Used to identify mechanical characteristic of the unit.


 Disc Magnet Stepper
 P X 5 3 2 -25 8 12 14
 P  Disc Magnet Motor
X  Internal Code
 5  Diameter
 3  Length
 2 Motor version
2 = Full/half-step
0 = Microstep
 25 Number of rotor pole pairs
 8 Number of connections or terminal wires
 12 Resistance per winding
 14  Motor execution code