Understanding Auto Sensing in Washing Machines: How Load Size is Automatically Detected in Washers?

Modern washing machines have many innovative technology and features to aid a seamless laundry experience. These innovations help minimize human intervention and automate the washing process. One such brilliant technology in automatic washing machines is automatic load sensing.

Automatic Load sensing has become a common feature in almost all modern washing machines. The washer senses the load present in the tub and automatically fills the required amount of water. But how do the washers sense load size accurately and fill the water appropriately? Let us find out in this article.

How Does Washing Machine Sense Load Size

How Does Washing Machine Sense Load Size?

A Washing machine senses the load size and fills the water accurately with two different components.

First, the washer analyzes the current required for the motor to turn the tub and senses the load. Then accordingly, the water starts to fill in the tub until the water level sensor or pressure sensor detects the achievement of the required water level. When the appropriate level is achieved, the washer simply proceeds to the next step in the wash cycle.

Let us now understand how this sensor works in detail for both top load and front load washing machines.

Automatic Load Sensing in Washers

As we mentioned earlier, the laundry load is not directly weighed by the washers. Instead, the washer tries to analyze the current required to turn the loaded tub and understands that there is a load in the washer. Here is a step-by-step process on how this works:

  • The motor drive of the washer knows the resistance provided by an empty tub as opposed to a loaded tub
  • This is achieved by calculating the current required to turn an empty tub and a loaded washer tub
  • When you load the washing machine, first the tub does a single spin with the help of a motor drive. The control unit senses the torque used for turning the loaded tub using the current drawn.
  • This provides the washer with the load size available on the tub. Using this, the washer starts to fill the tub with water.

To fill the tub with the appropriate water level, the following procedure is used by the washing machines:

  • After loading the tub, first, the washer checks the lid lock by powering up the lid switch.
  • When the control ensures that the lid is locked, the washer slowly turns to recognize the load size using the current drawn by the motor.
  • Now, the washer unlocks the lid briefly and then locks it again
  • After locking the lid for the second time, the washer tub will slowly turn while the water starts to fill the tub
  • The tub will stop for small intervals to let the water soak in the clothes. This will enable the washer to measure the right water level without overflowing or under-filling.
  • As the water soaks in the clothes and fills, the tub slowly spins to make sure all the clothes are completely wet. Once all the clothes are sufficiently wet, naturally the water will start to rise in the drum or tub
  • The water level gradually increases and the water level sensors come into play. The water level sensor estimates the level in the tub and verifies it with the wash cycle chosen.
  • Once the appropriate level is achieved, the sensor cuts off the water inlet valve and starts to rinse the clothes.
  • The water level will also adjust according to the size of the load and when there is an excess water in the tub, it is drained to reach the appropriate level.

This is how the automatic load sensing works in all modern washers. The washers don’t directly measure the weight of your laundry. Rather they simply take into account the current drawn by the motor and the water level sensors help in filling the tub accordingly.

What is the Primary function of the automatic load sensing feature in washers?

The primary function of automatic sensing is to reduce the amount of water used for washing the clothes. With the help of auto-sensing technology, the washer knows how much water is to be filled and ensures enough water is added to the tub. This reduces water consumption and makes the washer energy efficient.

Apart from this, the auto sensing works to adjust the spin speed, adjust detergent dispense, and work according to the wash cycle chosen.

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