Device for automatically cutting off an electric motor

摘要

A permanent magnet (16) is seated in a rotationally fixed manner on the shaft (10) of an electric motor in order to cut said electric motor off automatically. When the shaft (10) rotates, the permanent magnet (16) drives with it an eddy-current body (24) which is seated on the shaft (10) such that it can rotate freely. The eddy-current body (24) is moved against a stop (28) which is flexible in a resilient manner and, when the stop (28) is deflected against its spring force, switches a switch on for supplying electrical power to the electromagnet. If the shaft (10) is blocked, eddy currents are no longer produced in the eddy-current body (24) and the sprung stop (28) moves the eddy-current body (24) out of its position where it operates the switch, so that the electrical power supply to the electromagnet is automatically cut off. <IMAGE>