Motors in magnetic environments

Non-magnetic drive systems with piezo effect. Motors that operate without the need for their own magnetic fields or magnetic materials can solve technical problems in numerous applications. Especially when magnetism is needed for diagnosis or therapeutic purposes.

The most basic principle of the electric motor can become a problem in some applications: Magnetic Resonance Imaging scanners, particle accelerators and also electron microscopes use magnetism. Magnetic fields in electric motors, which can reach several tesla, are the cause of unpleasant interactions. Either the motor is degraded in its functionality and precision ability, or the motor itself causes undesirable effects. Such problems are prevented with motors that operate on the basis of piezoelectricity.

In addition to a large selection of linear motors, PiezoMotor also offers rotational motors in a non-magnetic version Credit: PiezoMotor

PiezoMotor of Sweden specializes in the development of miniature motors that use the patented Piezo LEGS^® technology. In this technology, electric voltage is applied to actuators made of piezoelectric ceramic material, which then expands or deforms. This can power a ceramic rod with linear motion in nanometre steps at speeds of up to 15 mm/s. The effect is similar in rotational motion except that a disc is set in rotation. The actuators hold their position with mechanical stability. And because they consume no energy in off-load state they do not heat up.

Most motors from PiezoMotor, such as the Piezo LEGS® Linear Twin LT40, are available both for normal environments and in a non-magnetic vacuum version Credit: PiezoMotor

A piezo motor needs no magnetism

The advantage of piezoelectricity is that without the windings needed in a electric motor, there is no source of magnetic flux on the one hand and cannot be disturbed by it on the other. PiezoMotor offers completely non-magnetic motors with appropriate housing materials and non-magnetic alloys that are suitable for use in an MRI scanner without negative effects on the image. MRI robots for surgery and precision therapy devices using positron emission tomography (PET) have successfully been equipped with motors from PiezoMotor. The use of the standard motors or custom solutions is also possible in other areas where electromagnetic disturbances are a problem.