Shown for the belt conveyor integrated protection circuit . The protector from car circuit, fault protection circuit , speed protection circuit , deviation circuit, buck rectifier circuit and other components. The car circuit by the start button QA, IC1 (555), IC2 (555), J1 and other components. When you press the QA , the buck rectifier circuit output +12 V voltage is applied to IC1, IC2, so that relay J1 pull , starting bell rang . When the newly combined +12 V of the voltage , IC1 pin potential is low because ? (C1 mutation on the voltage can not ) and place set, while C1 is charged through R1 , when the C1 charge potential to make IC1 feet higher than the 2 / 3VDD time, IC1 reset . C1 of the charging time shall be the appropriate starting delay time td = 1.1R1C1, icons corresponding parameter is about 5 minutes. T within the dashed box for the coal level sensing probe . When the conveyor belt of coal -bit high touch to T, 555 -pin potential is low because ? (<1/3VDD) and place set, so that J2 release , electric shock and J2-1 and the starter off , motor stop D Switch , bell alarm . Speed protection circuit mainly by the speed sensor ( magnet , reed switch ), IC1, IC2 and other components. When the normal speed underground transport (96 r / min ), the rate of protection does not occur . When the speed dropped to less than 48 r / timeshare , reed fewer conduction , 555 feet ? potential is high due to (> 2/3VDD) and the occurrence of reset , ? the output pin low to trigger IC1 home Bit , so that J2 release starter disconnect , stop the running belt . Deviation of protection achieved through the trip switch . When Belt Running , the trip switch to IC2 feet grounded, IC2 is forced to reset , so that IC1 Set , J2 release , motor power shutdown , while alarm bells . The circuit can coal position , speed, belt, deviation detection and control , with the start alarm, fault alarm and starting speed self-preservation and protection of locking and other features .