Page 8 of catalogue Drive technology for AC and DC of ebm-papst Mulfingen GmbH & Co. KG

Motor technology

The most distinct advantages of this type of motor: The EC motor sidesteps the disadvanTo produce a motor torque, the field windings in the stator of the motor tages associated with the mechanical commutareceive a current. The resulting magnetic field reacts against the permator such as, commutator wear, brush friction, nent magnetic field of the rotor, generating a torque. accumulation of dust due to abrasion, noises, In order to ensure that the rotor continuously rotates, the current in the starting difficulties due to corrosion of the winding must be commutated. In conventional DC Motors, the commutation commutator segments and high-frequency necessary for constant rotation of the armature is achieved mechanically interference caused by sparking. using a commutator and brushes. Thanks to modern semi-conductor technology, this mechanical commutation can be replaced by a non-contacting, A distinguishing feature of the EC motor is its electronic circuit. compact size. Furthermore, the commutation electronics can be equipped at comparably low The magnet is in the form of a rotor, and field windings that are distributed cost with an electronic control unit for maintaiover the circumference of the stator are each connected to the voltage ning a constant speed. The rotor position sensource via one or more transistor switches. The transistor switches are sors are additionally used for determining the controlled depending on the position of the magnetic rotor. For determining actual speed. The considerably better service the position of the rotor, Hall effect sensors are used-, one or more rotor life values in comparison to the brush DC position encoders positioned on the printed circuit board of the motor. Such Motors are also a major feature. motors are referred to as electronically commutated motors, in short EC motors.

Electronic motor commutation

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