Structure and working principle of drainage motor of washing machine

The drain motor and drain electromagnet of automatic washing machine have the same function, but the structure is different. AC drainage motor is widely used in automatic washing machines because there is no contact impact sound and electromagnetic sound between armature and iron core when the drainage electromagnet is energized and attracted. Let's take a look at the structure and working principle of the drain motor of the washing machine.

Drainage motor

Drainage motor is mainly composed of micro synchronous motor, transmission, traction wire rope and travel switch. When draining water, the microcomputer board (or program controller) supplies power to the micro synchronous motor of the water supply and drainage motor, and the synchronous motor rotates, and the steel wire rotates around the rotating water drainage motor at a low speed through gear speed change, and the steel wire rope pulls the connecting arm, which pulls the drain valve plug to overcome the elasticity of the valve spring to open drainage, and at the same time pulls the clutch brake arm. When the steel wire is wound in place, the travel switch acts. When the drainage motor is cut off, the drain valve plug is reset under the elastic force of the valve spring to stop drainage, and the steel wire of the drainage motor is pulled out.

Working principle of drainage motor

There are two trips during work:

In the first stroke, that is, when washing, the drainage motor is energized, the connecting rod of the drainage motor is pulled back for a certain distance, and the small valve tube of the drainage valve is pulled away for a certain distance, so that the clutch brake band is loosened, and the dewatering bucket is in a free state (the dewatering bucket is locked when washing in an ordinary washing machine), so that the inner bucket rotates and interacts with the pulsator to produce the hand rubbing effect when washing;

In the second stroke, that is, in the process of drainage and dehydration, the drainage motor moves for the second time, pulling back all the connecting rods of the drainage motor, pulling away all the drainage valves and simultaneously pulling away the pawls to realize the drainage and dehydration function. Therefore, the drain motor of the hand washing machine has three states: free state (i.e., non-working state without power supply), first stroke state (i.e., washing state) and second stroke state (i.e., drain state and dehydration state), which are explained respectively below.

(1) free state

In the free state, the drainage motor is not energized and is in a non-working state. At this time, the connecting rod of the drainage motor is fully extended (the motor end cover has been opened), and the internal contacts of the drainage motor are as follows: No.2 and No.3 terminal contacts are disconnected, and 1 and No.3 terminal contacts are connected. At this time, the resistance between terminals 2 and 3 measured by multimeter should be infinite; The resistance between the terminal 1 and 2 should be 4kΩ-5kΩ, which is the parallel resistance of the electromagnetic coil of the drainage motor and the micromotor. The resistance between terminals 1 and 3 should be infinite.

(2) First stroke state

The first stroke state is that the drainage motor is in the washing state. At this time, the connecting rod of the drainage motor is pulled back to one end distance, and the small valve tube of the drainage valve is pulled open. The internal contacts of the drainage motor are connected as follows: 1 and plug-in terminal No.2 of the drainage motor are connected; Contacts of No.2 and No.3 plug-in terminals are disconnected. At this time, the resistance measured by multimeter between plug terminals 1 and No.3 should be around18kΩ, which is the series resistance of the electromagnetic coil of the drainage motor and the micromotor. The resistance between the terminals of No.2 and No.3 plug-ins should be about 6kΩ, that is, the resistance of the micromotor of the drainage motor; The resistance between the plug terminal 1 and 2 should be 1 1kω~ 12kω, which is the resistance of the electromagnetic coil of the drainage motor.

(3) the second stroke state

The second stroke state is that the drainage motor is in the state of drainage and dehydration. At this time, the drainage motor is energized, all connecting rods of the drainage motor are pulled back, and the drain valve plug is opened to realize drainage. The connection and disconnection of the internal contacts of the drainage motor are as follows: the terminal contact of No.2 plug-in of the drainage motor is disconnected from the terminal contact of 1 and 3. At this time, the resistance between 1 and plug-in terminal No.3 measured by multimeter is infinite. 1 and No.2 plug-in terminals are connected with the electromagnetic coil of the drainage motor, and the resistance between them is 1 1Kω~ 12Kω, that is, the resistance of the electromagnetic coil; The resistance between plug terminals 2 and 3 is infinite.