Patents Represented by Law Firm Jones, Askew & Lonsford
  • Patent number: 4694371
    Abstract: A protection circuit for stalling protection in commutatorless direct current motors is driven by Hall generators, in particular Hall IC's. A respective semiconductor circuit element (5, 14) disposed in series with each stator winding (1, 2) is turned on or off in dependence on a control voltage induced in the stator windings (1, 2). The control voltage (U.sub.B) is constituted by the sum of the operating voltage in the unenergized windings (1, 2) and the counter-e.m.f. induced in these windings, whereby, if the sum of these voltages is greater than the operating voltage, the semiconductor circuit element (5, 14) connected to the respective energized winding (1, 2) is turned on, and, if the counter-e.m.f. is zero or falls below a predetermined cut-off value, the respective semiconductor circuit element (5, 14) is turned off.
    Type: Grant
    Filed: May 3, 1985
    Date of Patent: September 15, 1987
    Assignee: ebm Elektrobau Mulfingen GmbH & Co.
    Inventors: Wilhelm Reinhardt, Helmut Lipp