MACCON specializes in the development and supply of switched reluctance (SR) and synchronous reluctance (SyR) motors.

Reluctance motors are based on the magnetic reluctance principle, which utilizes the magnetic attraction of an electromagnet to iron. SR motors are characterized by distinct stator and rotor poles. On the other hand, SyR motors have a traditional stator while the rotor is round and possesses an inner structure with magnetic paths of varying reluctance symmetrically distributed around the rotor.

The SR motor has a different number of stator and rotor poles. Both the rotor and the stator are laminated to reduce eddy current losses. Each stator pole has an excitation coil. The opposing poles are electrically connected to form the North-South pole pair of a phase. The phases are controlled by two electronic switches in a specific current direction pattern. Continuous torque is achieved by correctly switching the phase currents with respect to the angle.

The following is an overview of the key features of switched reluctance motors and synchronous reluctance motors:

Switched Reluctance Motors (SR Motors):

  • Distinct stator and rotor poles
  • Laminated construction of rotor and stator to reduce eddy current losses
  • Each stator pole has an excitation coil
  • Opposing poles are electrically connected to form North-South pole pairs of a phase
  • Phases are controlled by electronic switches in a specific current direction pattern
  • Proper sequential switching of phase currents leads to continuous torque

Synchronous Reluctance Motors (SyR Motors):

  • Traditional stator and a round rotor with an inner structure
  • The inner rotor structure provides magnetic paths of varying reluctance symmetrically distributed around the rotor
  • Laminated construction of the rotor to reduce eddy current losses
  • The stator is controlled by excitation coils
  • A continuous torque is generated through the specific arrangement of reluctance paths in the rotor

Both types of motors offer specific advantages and characteristics that make them suitable for different applications. Switched reluctance motors provide easy control and high torque at low speeds. On the other hand, synchronous reluctance motors offer high efficiency and a wider speed range.

MACCON has extensive experience in the development and optimization of switched reluctance and synchronous reluctance motors. Through innovative technologies and customized solutions, we can meet the requirements of our customers in various industries. Our motors are characterized by high quality, reliability, and performance.

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Key features of switched and synchronous reluctance motors

The most important characteristics of this technology can be summarized as follows:

  • Efficiency: The efficiency of SR motors is comparable to permanent magnet motors in all 4 quadrants. The values reach more than 85% in a wide range of operation. Compared to conventional AC induction motors the SR motors often have an advantage (especially in the middle speed range).
  • Controllability: The SR motor can be operated in all 4 quadrants. Due to the unipolar design the driving electronics is quite simple. To achieve less torque ripple some more sophisticated design is necessary.
  • Robustness and Reliability: The SR motor is as robust as conventional AC induction motors, since the rotor is pure iron. In case of a winding fault these motors are better protected than other motor technologies.
  • Audible Noise: The audible noise during operation is as good as other technologies; new lamination designs and driving algorithms promise further improvement.
  • Speed Range: The SR motor  can be operated over a wide speed range. In this characteristic it is similar to a vector controlled AC induction motor with constant torque at low speed and constant power at high speed.
  • Peak Torque: The SR motor offers a by far higher eak torque than an induction motor of the same size; but it cannot reach the value of a similar sized permanent magnet motor.
  • Power to Weight Ratio: Also here the SR motor has advantages over the AC induction motor. For a given power the SR motor is about 40% smaller and lower weight than the AC induction motor. There is no physical limitation for the power of SR motors; SR motors have been developed for a power range of 50W to 5MW!

MACCON is a leading supplier for SR technology worldwide. We perform research and development to explore further possibilities for the design and usage of SR motors in various applications. An example is the transversal-flux, reluctance machine.

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Do you have technical questions or need a quote?

Contact us today to talk to an experienced MACCON engineer!