The washing machine timer is an automatic control switch, which has two functions: one is to control the total working time of washing machine dehydration, washing or rinsing; the other is to control the rotation direction of the washing machine motor, so that the motor according to the predetermined cycle program Perform positive and negative reversal to achieve the purpose of washing or rinsing laundry. In fact, this kind of timer is not only used for washing machine timing, but also widely used in household appliances, such as timing for electric fans, but the timing range is different. According to the structure of the timer, it can be divided into two categories: mechanical timer and electronic timer.
At present, the washing machines produced in China use mechanical timers, which are widely used in the home appliance industry, and mechanical timers are widely used in washing machines. This is because mechanical timers are easier to manufacture, less expensive, and easier to maintain than electronic timers. However, with the increasing requirements for automation and program control, mechanical timers are difficult to meet the requirements. From the perspective of development, electronic timers are indispensable for high-end washing machines. Fully automatic washing machines for large-scale integrated circuits and advanced fully automatic washing machines with micro-processing control have emerged. According to the function of the timer, it can be divided into the dehydration timer, the strong wash timer, the strong, the medium wash timer, the strong and weak wash timers. The dehydration timer is used to control the dehydration time. The timing range is 0-5 minutes. During this period, the energized contacts control the steering of the motor to be fixed. The strong wash timer has a set of contacts for controlling the total wash or rinse time, with a timing range of 0-15 minutes.
In addition, there is a set of single-pole double-throw contacts, which control the cycle of the motor's positive and negative cycle cyclic commutation during this total time, each commutation period is about 30 seconds, and the stop time is 5 seconds. The total time of the strong and medium wash timers is also 0-15 minutes, the strong wash cycle is 30 seconds, and the strong wash function of the stop cycle for 5 seconds is also retained. In addition, a third set of single-pole double-throw contacts is added, and the set of contacts is used to control the forward and reverse direction of the motor, the commutation period is 4 seconds, and the stop time is 9 seconds. The structure and function of the three sets of contacts of the strong and weak wash timers are exactly the same as those of the strong and medium timers. Only the commutation period of the third group is shorter than 4 seconds, and the stop is slightly longer than 8 seconds. Weakly wash the contact set. In fact, in the case of moderate or weak wash, the timers with the third set of contacts are collectively referred to as strong and weak wash timers for simplicity and uniformity.