| 摘要 |
FIELD: electric engineering. SUBSTANCE: device has final-control unit and driving unit. Detector is designed as current transformers with resistive load, four voltage scaling circuits, comparator and starting unit, which effects final-control unit and driving unit, when protection is required, by means of hyperbolic overload response (dependence of overload time and its multiplicity). Comparator and starting unit may be designed using digital CMOS-circuits. "Heavy start" (used in devices which have long overload characteristics during start) may be achieved by introduced time-setting unit, which has passive capacitor divider or master oscillator, pulse counter and control circuit. Time-setting unit finishes or continues pulse counting depending on mode of load. This effects driving unit. EFFECT: increased functional capabilities, increased reliability of protection. 4 cl, 2 dwg |
