Telma induction brakes, commonly known as electrical or electromagnetic retarders, offer an endurance braking system. They dissipate a large part of the braking energy, thus relieving conventional braking systems.

Telma induction braking systems dissipate the braking energy by generating eddy currents.
The Telma is comprised of a fixed stator and a pair of rotors that are attached to and rotate with the driveline.

The stator and the rotors are mounted coaxially, opposite to one another, and are separated by a narrow air gap, thereby avoiding any friction.

The stator plays the role of the inductor; it contains several electromagnets, which generate magnetic fields when electricity continuously flows through the stator coils, thereby producing eddy currents in the mass of the rotor.

The rotors play the role of the armature. Manufactured with a specially designed conducting material, the rotors are subjected to eddy currents generated when they rotate through the magnetic fields created by the stator.

By definition, eddy currents originate from conducting metallic masses when the latter are placed in variable magnetic fields. In the case of Telma induction braking systems, the variability of the magnetic fields to which rotors are subjected is a result of the rotation of the rotors. Eddy currents, also known as swirling currents, wrap around the magnetic flow lines.

The generation of eddy currents in the mass of the rotor leads to the appearance of Laplace forces that counteract with the rotation of the rotor. The braking torque that is thus generated and applied to the drive shaft slows the vehicle.

The eddy currents produce a gradual rise in rotor temperature and the heat is then dissipated into the air through the rotor cooling vanes. With Telma induction braking systems, it is thus possible to effectively slow down a rotating shaft without friction and therefore without wear.

Although induction braking systems might seem simple in principle, they involve complex physical laws such as materials resistance principles, electromagnetism, thermodynamics and fluid mechanics.
Telma's recognized expertise in the field of electromagnetic induction braking systems is based on the detailed modelling of all physical laws involved in the operation of induction braking systems. This modelling has been enhanced by years of practical experience and laboratory testing that have proven to make ​​the difference.