Options
Patent
Title
Verfahren und Vorrichtung zur Blockiererkennung eines Elektromotors
Other Title
Process and device for detecting the blocking of an electric motor
Abstract
A device (1) serves to detect the blocking of an electric motor connected to an a.c. power supply (Ph, Mp), said device having a measuring instrument (4) for measuring the e.m.f. voltage of the motor (10), a control device (2), a synchronizing device (3) and an off button (5). The off button (5) has an actuator (9) switched in series with the motor (10). With the help of the control device, the off button is controlled so that the flow of current to the motor (10) is interrupted for one a.c. voltage period, following which current is allowed to flow again during a voltage half-wave which is of opposite pole to the last voltage half-wave of the current-flowing phase. In this last current-flowing phase, there is an increased current drain and, as a result, there is a greater e.m.p. signal when the e.m.p. voltage is measured. As a result of this large e.m.p signal, the difference of the e.m.p. voltages between the blocked and non-blocked operating states of the motor is much greater and c an thus be evaluated more easily and more reliably (Fig. 1).
Inventor(s)
Konstanzer, M.
Patent Number
1992-4231806
Publication Date
1993
Language
German