| 摘要 |
PURPOSE: An overload isolator of a hoist and a crane is provided to protect an equipment from overload by sensing overcurrent flowing through a power wire of a motor in driving a hoist and a crane, displaying the sensed state and isolating operation of a rising switch in a control unit. CONSTITUTION: An overload isolator of a hoist and a crane consists of: a current sensor(2) detecting the electric current state of a motor(11) through a CT(Current Transformer); a comparator(6) converting the analog output of the current sensor into digital data, comparing the digital data with input digital data of a deep switch(8) and a key pad(9), and outputting the corresponding digital data; an alarm unit(7) consisting of an LED(Light Emitting Diode) and a buzzer driven in overload of the output from a switch drive unit(3) and the comparator; a displayer(4) displaying the electric current value in the overload; and a control unit(1) outputting control signals to the switch drive unit, the displayer and the alarm unit. In case of the overload state of a hoist and a crane, the buzzer and the LED are driven. A worker recognizes the overload state of the equipment by referring to the alarm unit and the displayer. Therefore, the worker takes prompt action on the overload to prevent the equipment from damage.
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