Robert Boschgmbh

Wolfgang Sohn

Adolf Mohr

Georg Strobl

To test the flux of circular segmental permanent magnets for assembly in permanent magnet dynamo electric machines, typically electric motors, a gauge is made of soft iron having an inner segmentally circular soft iron core, on it a layer of non-magnetic material to simulate the air gap of the motor, space for the permanent magnet to be inserted, and a return soft iron yoke in magnetic circuit with the core. A measuring coil which is chorded is located on the gauge to sense the magnetic flux, and so placed on the core that it conforms, at least approximately, to the pitch angle of the armature winding of the dynamo electric machine with which the magnet is to be used. To simulate cross fields, a demagnetization widing can be placed in the space adjacent the layer of nonmagnetic material adjacent the ends of the space for the permanent magnets to be tested, or the core can be cut with grooves similar to the coil slots of the armature, with current being passed therethrough in a direction to simulate the armature cross field. The test apparatus can be combined with a magnetizing yoke carrying magnetization coils to magnetize the segments, test them, and then demagnetize the segments, and reversely magnetize them for test of uniformity. Magnetic sensors can be placed on the core to sense the localized flux distribution of the magnetized magnet elements.

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Buhl-Vimbuch, Germany

Wolfgang Sohn