Refrigerators Frequency Converters Motor Overheat Protection PTC Thermistor MZ3-B-47ROM for Motor Starter in Air Conditioner

The motor starter utilizes the current-time characteristic of PTC ceramic. When voltage is applied to the PTCR, a large current I begins to flow through. After a certain period of time ts, as the temperature of the PTCR rises, the resistance value increases rapidly, causing the current to drop sharply. During this period, ts can range from 0.1 seconds to several seconds. Its value depends on the heat capacity, resistance value, heat dissipation conditions, load resistance and working voltage of the PTCR. When the external voltage is removed, the PTCR will cool to the resistance value at room temperature. Based on this principle, it has been widely applied in the motor starting of household appliances such as refrigerators and air conditioners. It should be noted that when using the delay performance of PTCR, if the same delay time is to be repeated, a certain interval time tr (i.e., the so-called recovery time) should be set to allow the PTCR to return to its original state temperature. Therefore, immediate repetitive actions should be avoided; otherwise, the PTCR cannot provide a continuous large current, causing the compressor to fail to start working normally and potentially leading to compressor burnout.