Search for PM Step Motors
You can find the Permanent Magnet (PM) step motor you need right here. Select the Find It Now button above to view a listing of all the Permanent Magnet step motors that NMB has to offer.
A permanent magnet motor, sometimes called a “tin can” motor, can be advantageous in that permanent magnet motors have extremely low inertia and their magnetic flow path is optimized, with no coupling between the stator windings as found in variable resistance motors.
About PM Motors
In a PM motor, the rotor is moved through the action of the permanent magnets, rather than through “teeth” as in the classic variable resistance step motor. This results in improved torque characteristics for PM motors over the VR step motor.
Permanent magnet stepper motors are a cost-effective alternative to hybrid stepper motors in applications requiring less accuracy and less torque than the hybrid motor offers. Step angles range from 3.75 degree to 18 degree with typical positioning accuracy of +/- 10%.
What Makes a “Permanent Magnet” Permanent?
A permanent magnet is defined as an object that is magnetized to produce its own persistent magnetic field. It is permanent because the object remains magnetized, meaning it will always exert an attractive or repulsive force on certain other objects, which are referred to as ferromagnetic. The permanent magnet in a motor is a rare earth magnet, which means it is made from rare earth metals.
This does not mean that the motor containing a permanent magnet will be particularly difficult to find: The term rare earth refers the rare earth minerals where these metals were initially found. In fact, rare earth metals are plentiful and a motor made with permanent magnets can be very reasonably priced.
If you’re looking for a motor with better torque characteristics than a standard variable resistance motor, a PM motor is probably for you. If you’re finding that even the PM motor is not providing the level of performance you need, you may want to upgrade to a hybrid motor, which is a motor that has the teeth of the variable resistance motor with the magnetic action of the PM motor for extra accuracy.