The application of single phase ac asynchronous motor in washing machine
Washing machine motor should be called: capacitive single-phase asynchronous motor. The principle is on the startup winding in series a proper capacitor, due to the capacitor current lagging behind its voltage 90 degrees, so can produce a deflection on the stator magnetic field, the motor rotation. A washing machine is a clean appliance that USES electricity to produce mechanical functions to wash clothes. The washing capacity is divided into two categories: household and collective. China requires washing capacity in under 6 kg belong to household washing machine: household washing machine mainly by the body, wash to take off the bucket (some wash and take off the bucket separately), drive and control system, etc, some still is equipped with heating device. Washing machines generally refer to the use of water as the main cleaning fluid, which is different from the use of special cleaning solution and usually the dry cleaning which is responsible for the special person.
The machine that drives the washer is the motor. Selecting the motor at present, the washing machine has the following kinds: single phase ac asynchronous motor, single-phase series motor, permanent magnet brushless dc motor and switched reluctance motor. It is divided by the structure of the motor and the way of work; If the connection mode of the motor and load is divided, it can be divided into indirect drive and direct drive. Direct drive, the output shaft of the motor is directly connected with the load, and eliminates the central driving chain, which is a kind of both a short and advanced drive. The motor that carries out this type of drive is the direct drive motor. The tube says: direct drive motor. It's also called DD motor in English.
The driving system of the washing machine is complex, the work efficiency is low, the speed is unstable, the start-up current is large, the failure rate is higher, the control precision is low. (2) on the structural setting, washing machine motor shaft and the center of the drum shaft can't coaxial (need belt deceleration), in a state of bias, and it is this "offset" optimum become washing machine vibration occurs at work, hard to balance. So, we have to increase the growth of the implant to inhibit the vibration of the whole machine. (3) the intrinsic structure and external properties of the motor determine the low power, weak starting moment, insufficient capacity of overload and poor controllability. At the same time, it is difficult to implement direct drivers. And so that the inherent structure and performance of the single phase ac motor has to some extent, restricted the further development of the washing machine, such as difficult to achieve a variety of washing speed design, machine and washing machine a variety of self protection function, frequency the sunrise start, etc., so need to develop a new type of motor is suitable for washing machine work.
Single phase ac asynchronous motor, which is is generally used to washing machine motor, the reason is tube sheet, because everyone has its principle, the structure is very understand, production technology has been very mature, and applied in the washing machine has decades of history. But as a result of this kind of motor is constant speed operation, when working through the belt drive and deceleration clutch to complete the conversion speed, torque, then finish washing machine washing, dehydration, respectively. The normal drum washing machine does not have a decelerating clutch, and only the first one is a reduction and transmission. It is accomplished by different poles of the motor in the washing and dehydration. The winding is made up of two poles/l2 poles or two poles/l6 poles. This will allow the washing rate to be around 40-60r/min, and the drying speed is about 400 to 600r/min. When people want to further improve the dehydrated speed, they also choose to change the voltage of the motor to change the voltage of the motor winding, which can be adjusted for dehydration. However, this method exists, the regulation range is small, the stability is poor and so on.
