Why a Can Stack Motor

Canstack Diagram

The permanent magnet stepper and AC synchronous motor were invented by a design team that Portescap can trace its roots back to. Today, this technology is found in a wide variety of applications for good reason – they have the accuracy and torque to match the needs of our customers. Portescap has one of the broadest range of can stack solutions on the market today. Portescap’s can stack motors are intentionally basic to deliver a simple and effective motion solution for your application.

Can stack motion technology focuses on simplicity. This permanent magnet stepper motor uses the simplest of techniques and designs to create an effective solution for many applications, where reasonable accuracy and moderate torque are required. Portescap can trace its stepper heritage back to the invention of the can stack step motor. This is one reason why we offer one of the widest ranges of motors in the industry today, ranging from 15 mm to 42 mm in the permanent magnet family.


The stepper motor is an electromechanical device that converts electrical pulses into discrete mechanical movements, and therefore can be operated directly from a pulse train or a microprocessor. The shaft of a stepper motor rotates in discrete step increments when electrical command pulses are applied to it in the proper sequence. The motor’s rotation has several direct relationships to these applied input pulses. The sequence of the applied pulses is directly related to the direction of motor shaft’s rotation. The speed of the motor shaft rotation is directly related to the frequency of the input pulses and the length of rotation is directly related to the number of input pulses applied. Error is non-cumulative as long as step integrity remains. Step angles for Can stack motors are usually 3.6 degree to 18 degree (or 100 steps per revolutions to 20 steps per revolutions).

Can stack motors are usually 2 phase in construction. They consist of two stator cups with claw tooth poles formed around a winding creating each half of the motor. The rotor has the same number of pole pairs as the stator. The poles on each stator cup are constructed to be a half a pole pitch apart. With two coils this means there can be 4 discrete positions per pole pitch. A 2-phase motor, for example, with 12-pole pairs in each stator / coil sector will therefore have 48 steps per revolution or 7.5 degrees per step.

CanStack Inset


Details Characteristics Advantages
Radially magnetized permanent magnet rotor High torque to size ratio Overall machine size reduction
Bobbin wound coil design Unpiolar/Bipolar windings can be designed for optimum performance Optimizing motor output for power input
Sintered bronze bearing design – Ball bearings option Long life lubrication Increased lifetime for the machine
Step angle variation – 3.6 degrees to 20 degrees Design capability for finer mechanical resolution Finer motion resolution
Simple motor construction Simple mechanical construction with proven design characteristics Cost effective motion solution