Competition is ~ relay contacts contactor control systems often encounter problems, too much trouble to deal with, and sometimes need to add a lot of elements to add. However, if the use of negative temperature coefficient thermistor (NTC) delay switching
characteristics, can easily and effectively prevent relay contact competition. Circuit 11 in FIG. 6. It is the thermistor resistance RT larger at room temperature, through the current demand after a period of delay (about 0. 5s), the sharp decline in the resistance, time delay relay KAz pull to avoid contact with the contactor KM point competition dispute, avoid circuit out of control.