4.保护电路:该机心在开关电源的初级和次级均设有保护电路。初级的保护电路包括:限流保护、低压保护、过压保护、过热保护,一是确保开关电源初级厚膜电路 Q801不受过流、过压的冲击;二是在发生过压、过流、过热故障时,迫使 Q801停止工作,进入停机保护状态;开关电源次级的保护电路包括:+B 过压保护、+B 过流保护、场输出过流保护,当上述电路发生过压、过流故障时,保护电路启动,整机进入待机保护状态。(1)初级限流保护:由 R813、R812和继电器 SR81 4. Protection circuit: The movement in the primary and secondary switching power supply are equipped with protective circuits. Primary protection circuit includes: current limiting protection, low voltage protection, overvoltage protection, overheating protection, one is to ensure that the switch power primary thick film circuit Q801 from overcurrent, overvoltage impact; the second is in the event of overvoltage, overcurrent, overheating The fault, forcing Q801 to stop working, enter the shutdown protection state; switching power supply secondary protection circuit include: + B overvoltage protection, + B overcurrent protection, field output overcurrent protection, when the circuit overvoltage, overcurrent fault When the protection circuit starts, the whole machine enters the standby protection state. (1) Primary current limiting protection: R813, R812 and relay SR81