Ebm-papst St. Georgen Gmbh & Co Kg

Emb-papst St. Georgen Gmbh & Co. Kg.

Siegfried Schreiner

Hermann Rappenecker

Christian Rudel

Matthis Nickel-Jetter

Jörg Hornberger

Joerg Hornberger

An electric motor has a stator () as well as a rotor () rotatable about a rotation axis () and a sensor magnet () having an even number of sensor poles (). The sensor magnet () is configured to generate a magnetic flux having a magnetic flux density that changes sinusoidally with respect to the rotation angle. Two analog rotor position sensors () are arranged on a support structure () at a distance from one another such that, during operation, they generate two sinusoidal signals (B_S, B_S) having a phase shift of 90&#xb0; to each other. A signal generator () serves to generate at least one pulse-shaped signal (A, B) from the two sinusoidal rotor position signals (B_S, B_S) that are phase-shifted by 90&#xb0;. The instantaneous rotation speed can be accurately determined from this pulse-shaped signal.

Electric motor

An improved drum motor, preferably electronically commutated, features a unitary stationary central shaft () supporting a stationary inner stator (), and an external rotor (), including permanent magnets (), secured to an inner surface of a generally cylindrical rotatable casing part (). This permits variable speed operation while avoiding any need for an internal gear linkage. Safety is improved by making sealing plates () at respective axial ends of the casing () stationary, and providing an annular peripheral seal () around each sealing plate. Respective rolling bearings () near each end of the casing () facilitate rotation of the external rotor () relative to the stator (), and a clamping arrangement () minimizes noise from the bearings.

External-rotor motor having a stationary bearing shaft

An electric motor has a stator and an external rotor (). Its external rotor () has a sensor magnet () having a plurality SP of sensor poles (). The motor also has: at least one rotor position sensor () for generating a rotor position signal and a rotor position evaluation arrangement for generating an absolute value for the rotor position, which apparatus comprises an A/D converter () having a resolution of at least two bits, the at least one rotor position sensor () being connected to the A/D converter. In order to enable obtaining different digital values, even at rotational positions within the angle range of one sensor pole, each analog rotor position sensor signal is converted by the A/D converter into a digital value having at least two bits.

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Villingen-Schwenningen, Germany

Siegfried Schreiner