ebm-papst

About: ebm-papst is a company organization based out in Mulfingen, Germany. It is known for research contribution in the topics: Rotor (electric) & Stator. The organization has 572 authors who have published 736 publications receiving 3763 citations.

Electric motor with poles shaped to minimize cogging torque

Abstract: An electric motor has a rotor ( 36 ) and a stator ( 28 ) having a lamination stack formed with slots ( 126 ). The slots have a predetermined slot pitch (τ S ), and a multi-phase stator winding is arranged in them. The rotor ( 36 ) has salient poles having pole shoes ( 136 ) and a magnetic return path ( 130 ). Between the return path ( 130 ) and each pole shoe ( 136 ), a recess ( 138, 140 ) is formed for receiving a permanent magnet ( 38 ). On each side of such a permanent magnet ( 38 ), a region ( 146 a , 146 b ) of poor magnetic conductivity is arranged, in order to make the flux distribution in the air gap more sinusoidal. Measuring in a circumferential direction, the width (β) of a pole shoe ( 136 ) decreases with increasing distance from an interface ( 138 ) between said return path and said permanent magnet ( 38 ), and, at a place of lowest width, the pole shoe has an angular extent (β C) which has, with respect to the slot pitch (τ S ) between said stator slots ( 126 ), the following relationship: β C =n*τ S *(1−0.02) . . . n*τ S *(1−0.2), where n=1, 2, 3 . . . and β C and τ S are measured in mechanical degrees.

Method for determining the numerical value for the duration of a periodically repeated pulse signal, and device for carrying out said method

Abstract: The invention relates to a method for determining the numerical value for the duration of a periodically repeated pulse signal. The inventive method is characterized by the following steps: a) determining the periodic duration of the signal at intervals, b) determining a variable characteristic of the duration of the pulse of said signal at intervals, c) determining a numerical value characteristic of the signal from the periodic duration and the characteristic variable. Due to its shortness and accuracy the inventive method is especially useful for the application in electric motors. The invention also relates to a corresponding device.

Absolute encoder and method for generating an absolute value for an angle of rotation

Abstract: Disclosed is an electric motor (10) comprising a stator (12) and a rotor (14) with a shaft (87). The rotor (14) is provided with a sensor magnet (82) with a number SP of sensor poles (71, 72, 73, 74) for creating a predefined distribution of the magnetic flux density, wherein SP = 2, 4, 6, 8 etc. The motor further comprises at least two rotor position sensors (450, 455, 460, 465) for generating rotor position signals (B_S1, B_S2) which characterize the magnetic flux density. Said rotor position sensors (450, 455, 460, 465) are disposed in the region (30) of the circumference of the sensor magnet (82). The motor also comprises an evaluation device (32) that determines an absolute value (phi_el, phi_mech) for the rotational position of the rotor (14) from the rotor position signals (B_S1; B_S2). Also disclosed is a method for generating an absolute value for the rotational position of the rotor of an electric motor.

Method and apparatus for measuring a frequency datum

Abstract: An improved method, for obtaining a datum concerning the rotation speed (n) of a rotating object, such as a motor rotor ( 32 ), offers high precision. Typically, the motor has a sensor ( 61 ) which supplies a sensor signal that has, for each revolution of the rotor, a plurality A of events such as pulses or pulse edges which are counted by a microprocessor ( 23 ) associated with the motor. In order to keep the computation load on the microprocessor from increasing as the rotor speed increases, yet maintain high precision, the measurement is done over a full rotation of the rotor, starts at a first signal event ( 176 ), and ends after a third or nth signal event ( 182 ) which happens at the same rotational position as the first signal event.

Arrangement and method for removing heat from a component which is to be cooled

Abstract: An arrangement, for heat dissipation from a component that is to be cooled, features: a pump for pumping a coolant, which pump comprises a pump rotor; a fan that comprises a fan rotor associated with which is an electric motor to drive it, the pump rotor and the fan rotor being separated from one another in fluid-tight fashion and drivingly connected to one another via a magnetic coupling. It also relates to a method for heat dissipation from a component that is to be cooled, using a fan that comprises a fan rotor and a drive motor, using a pump that comprises a pump rotor, using a coolant that is pumpable by means of the pump, comprising the following steps: A) the fan rotor has a rotational motion imparted to it by means of the drive motor; B) the pump rotor has a rotational motion imparted to it, via the magnetic coupling, by means of the rotational motion of the fan rotor; C) the coolant is caused to flow by the rotational motion of the pump.