The composite method was presented according to the problems existed in the Matrah method,which method can only detect the contaminant between the contacts via measuring relay's static parameter.Based on the Matrah method,the relay's dynamic parameters is detected in the new method for detecting the contaminant between the armature and the polar,for example over-travel time,action time and so on.This test method can broaden the single sources for detecting,and strengthen the efficiency.The valid detection p...