(一)概述电力机车与电力传动内燃机车的主电路内,有很多低电阻的部件,如接触器触头、反向器触头、各种转换开关触头、牵引电动机大线线耳连接点、磁场削弱电阻和一些分路电阻等。当触头接触不良时,接触电阻增大,大电流通过时将使接触部件发热。过热后使接触面加速产生氧化层,氧化膜层过厚又加大接触电阻而形成恶性循环,以致发生机车主电路部件过热烧伤事故。磁场削弱接触器主触头接触电 (A) Overview Electric locomotive and electric drive diesel locomotive main circuit, there are many low-resistance components, such as contactor contacts, reversing contacts, a variety of switch contacts, traction motor line lug connection point , Magnetic field weakening resistance and some shunt resistance. When the contact is poor, the contact resistance increases, large current will make the contact parts heat. Overheating the contact surface to accelerate the oxide layer, the oxide layer is too thick and increase the contact resistance and the formation of a vicious cycle, resulting in locomotive main circuit components overheating burn accident. Magnetic field weakening contactor main contactor