| 摘要 |
Circuit providing rapid overload protection for an electric motor, in particular one for driving a mining machine running in difficult operating conditions, to protect the motor against excessive rise in the temperature of its windings during work involving large slippage, connected electrically in the circuit of an overload delay component of a static overload relay controlled in parallel with a zero-delay short-circuit component and with a decay component from three phase current transformers via a three-phase bridge rectifier, and containing a corrective component with regulated threshold systems, a delaying circuit and a logical product circuit, connected to the output circuit of the overload delay component controlling the overload relay, characterized in that in parallel with the input circuit of the overload delay component (1), connected to a regulating potentiometer (11) of the three-phase bridge rectifier (5), is the input circuit of the first threshold system (21) of the corrective component (2) set to a value corresponding to the current of the overload delay component (1), which is equal to or greater than the idle running current of the motor, and the input circuit of the second threshold system (22) of the corrective component (2) set to a value corresponding to a current less than or equal to the starting current of the motor, where the output circuit of the first threshold system (21) is connected in series via a delaying circuit (23) to one input circuit of the logical product circuit (24), while the output circuit of the second threshold system (22) is connected directly...<IMAGE>
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