How the washing machine Automatic Load Sense works?

1. How the washing machine Automatic Load Sense works?

I am working on the Automatic Washing machine project. I want to sense the Cloth load in the drum. I am sensing the wash motor current to measure the cloth load. Once i got the cloth load, I will take that much water quantity,rinse and spin time. What is my problem means:- In my wash motor with full load and no load also it is taking only 1.2Amps - (AC Induction motor). Then how to sense the cloth load. What's method for sensing the cloth load?.

2. Re: How the washing machine Automatic Load Sense works?

If you are saying the motor draws the same current regardless of the "cloth load" then, obviously, you can't sense the cloth load by measuring motor current, right?

I suspect the mass of the washer drum and drive components is significantly larger than the mass of the clothes, so you are trying to measure a very small percentage change in motor current.

3. Re: How the washing machine Automatic Load Sense works?

Then what will be solution?.
I have seen in some of the washing machine, they are not using any special sensors for measuring the cloth load. How they are measuring the cloth load?

4. Re: How the washing machine Automatic Load Sense works?

I will give you an idea, most washing machines know motor rpm in order to control spin speed right, so with a given power input acceleration = load!

•

5. Re: How the washing machine Automatic Load Sense works?

An induction motor, specially those dreary split phase devices are used, have so many no-load losses that they will obscure any additional current draw.
This in addition to the drum's high inertial load that will obscure the inertia of the wash load.

That is one reason, among many others, that fully featured modern washing machines utilize a BLDC motor.

•

6. Re: How the washing machine Automatic Load Sense works?

I do apologise I missed the "induction motor", all the ones I have seen in the last few decades have been series wound universal motors with phase control.

7. Re: How the washing machine Automatic Load Sense works?

From the above, seems like you are considering "cloth load" as the mere insertion within the washing machine drum; you migh know that dry clothes are significantly lighter if compared to wet, which is why modern washing machines have pre-setting for different types of fabrics since each one has a different water absorption capacity.

•

8. Re: How the washing machine Automatic Load Sense works?

That is one reason, among many others, that fully featured modern washing machines utilize a BLDC motor.
Then how does it overcome "This in addition to the drum's high inertial load that will obscure the inertia of the wash load."- the problem stays.

- - - Updated - - -

I have seen in the last few decades have been series wound universal motors with phase control.
My washing machine is Korean made (LG) and it too uses universal motor (too many wires are going to the motor and I cannot be very sure). Yes, some form of phase control is used for reversing.

9. Re: How the washing machine Automatic Load Sense works?

Universal motors would have at most four wires.
Two for the armature and two for the field.

Those are reversible. Non reversible have only two wires.

10. Re: How the washing machine Automatic Load Sense works?

In my whirphool washing machine, when load sensing starts the motor will run anti-clockwise (like spin) upto 8 seconds. Only three wires are flowing to the motor from the PCB.
1. Newtral
2. Motor CW
3. Motor CCW
At motor side capacitor is connected in parallel to the 2 and 3 . Two triacs are used for CW and CCW.
How they are sensing the cloth load? Help me to solve this problem....

11. Re: How the washing machine Automatic Load Sense works?

Originally Posted by nis2311
How they are sensing the cloth load?
These washing machines do not sense 'cloth load'; there are pressure sensors which detects the water level, and this somehow suffice for a rought estimate. As said, many of these equipment have option to define the type of fabric being washed, which help to give a more accurate estimate of the maximum required power to drive the motor.

12. Re: How the washing machine Automatic Load Sense works?

Sure, i know they are not using pressure sensor for the cloth load sense. The pressure sensor works only at water fill. If the water rises means the bottom side of the air will be pushed to the Pressure sensor, then we can identify the water level. What will be the solution to identify the cloth load. For a example a program called AUTO mode, in that it will be need to sense cloth load and wash the cloth according to the cloth load. Washing time and pattern need to match according to the cloth load.

13. Re: How the washing machine Automatic Load Sense works?

Do you really think there exists any kind of sensor capable to detect the fabric material? In addition, are you assuming that people will always put clothes made with the same fabric at each washing cycle? As said in other words, you don't need to know what type of clothes are within the drum, you only need to account the power required for each one (by measurements) and then setup the maximum power to be delivered. Since there is individual setup options of clothes, with this functionality, it become implicit the responsibility of the user to separate clothes, exempting you from adding any sensor to identify the material with which the fabric was made.

14. Re: How the washing machine Automatic Load Sense works?

It is not matter of type cloth. Mainly I want sense the cloth weight, it may be whatever fabric. I am sure there is no any sensors are not fixed. They are identifying by only agitation method (By rotating CW and CCW or rotating at Spin).

•

15. Re: How the washing machine Automatic Load Sense works?

Originally Posted by nis2311
I want sense the cloth weight, it may be whatever fabric.
Review reply #7: Wet clothes are much heavier than dry, so the weight of dry clothes is negligible in the laundry process. Again: Water absorbing capacity is perhaps the most relevant factor in this process, since during the first spin cycles of centrifugation most of the water will be drained as the more waterproof the fabric is.

17. Re: How the washing machine Automatic Load Sense works?

If you had the curiosity to search on the Web for the terms "washing machine auto sensing" would find that it is related the way as water is filled into drum, assuring that all the pieces will be wet after a time, therefore level sensor will actuate only when all the necessary water is added. As said before, each fabric has its own water absortion capacity.

BTW, looking at the comments from consumers from that specific brand on the video - which claims the "auto sensing" functionality on his washing machine - I was not able to find even a single compliment, only complaints, even in reports from other users elsewhere on the Web, stating that such a feature does not work as implicity alleged for that model.

How Sensing works and water amount determined: ... These sensing spins may take 2 to 3 minutes before water is added to the load. The washer will then move the load briefly, pause to allow water to soak into the load, and resume adding water.
This feature would make more sense in a front load washing machine (which is not the case in the video above) since the water is added flowing alongside drum surface, unlike that of the top load one, where the water jet drops over clothes.

Keep in mind that it is different to state sensing or sensor, and the unawareness of the subtle difference among both could lead to misleading. The "auto sensing" feature is rather a procedure to fill water, not a sensing algorithm at all

18. Re: How the washing machine Automatic Load Sense works?

It's easy to quantify the mass of clothes in the drum. A look at any Maytag schematic will reveal the algorithm used.
OP seems to want the answers to his homework or something, instead of a discussion about the physics and what sensors are available in his work.

--[[ ]]--