Analysis and maintenance: The reason for judging that the compressor has a "buzzing" sound and does not start is generally the fault of the starting relay. Because the refrigerator is used by a single-phase asynchronous AC motor, the motor has a starting winding and a running winding. The phase difference is 90°, and the refrigerator starter produced before the 1980s mostly uses the heavy hammer type.

The working process is as follows: when the refrigerator is started, the starting current passes through the contact of the starter to the starting winding, and the other way passes through the starter wire group to the running winding. The two channels work in parallel. When the motor reaches 70% to 80% of the synchronous speed, the starting winding automatically disconnects, and the starter will be overheated for a long time.

Under repair. Failure to switch to a damaged starter is quite common, because the ptc resistor has a simple structure and no contact. Seven arc and other advantages. Many repairmen use ptc resistors for direct substitution. In most cases direct substitution succeeds. It may also cause compressor damage to the fault v, so here to remind everyone to pay attention.

Theoretical analysis shows that when ptc resistance is used to replace the starter, the starting windings are connected with human resistance. At this time, the current scoop in the running winding has a fixed phase difference in the starting winding, and thus the torque generated. The value is small. Use only when it is easy to start. If ptc is used instead of the weight starter. It is necessary to string the ptc into the starting winding loop and remove the starter coil in series in the running winding, that is, the impedance value of the starter is reduced.

From the experimental characteristics of ptc. The current decay time in the starting winding is only about 1.5 seconds, such as the starting winding series resistance generated by the starting torque is small. It will inevitably cause the startup time to increase if the startup time does not match the ptc current decay time. 4-7 times the starting current is bound to be borne by the long-distance winding, which should be treated with caution. Therefore. Whether the ptc resistor can replace the heavy hammer starter is restricted by the choice of ptc and the refrigerator's own condition, temperature environment, heat dissipation capacity and many other factors, and should be treated according to the specific situation, and should not be forcibly replaced. So as not to cause the bad result of burning out the compressor.