GENERAL WORKING PRINCIPLE OF A WASHING MACHINE:
We put our clothes in, pour some water, then some detergents. The wash cycle begins, the mixture is strongly agitated, the dirt gets dissolved by detergent action, then we drain the dirty water. Again fresh water is poured, agitation begins, hence the clothes gets clearer after repeating a few cycles.
Afterwards, the clothes are transferred to the spin section, the unidirectional fast spinning motor rotates to squeeze water out of clothes. Hence clothes become drier and finally, we use natural or forced evaporation to get clean, dry and fragrant clothes.
Welcome, this is a tear-down of a semi-automatic washing machine. The company is Electrolux, 8 Kg, and top- load type.
Semi-automatic involves the involvement of the user itself to manually operate various procedures of the process.
- Water and detergent are poured by the user itself
- Timer and no of repetitions for the wash cycle is set again by the user
- The user himself has to transfer the clothes from the wash section to the spin section
Going through this general principle we have got two major circuitry for our machine:
Electrical circuitry to generate the mechanical force of rotation and plumbing circuitry to regulate the flow of water.To have a controlled motor operation we require the following components:
- Electrical circuits:
- Wash Motor
- Spin Motor
- To get efficient cleansing action we require following elements for Plumbing circuit
- Basic frame
- Spin gasket
- Agitator or Impeller
- The basic frame:
This frame provides two separate cabins for wash and spin section. The inner side of the wash section have smooth projections for rubbing of clothes and spin cabin is simply there to collect the water ejecting from the spin-gasket.
2. Spin Gasket:
The spin cabin is utilised for drying clothes to some extent after washing and rinsing.
The spin motor of higher RPM rotates the laundry in the spin gasket. The large centripetal forces push the water through the small holes on the dyer gasket. The water gets collected on the outer spin cabin and is drained out.
3. AGITATOR Vs IMPELLER:
One would find agitator and impeller arrangement in the top-load machine only. They work almost in a similar way but impact the fabric in different ways.
The impeller is a low profile cone or disc and driven by the wash motor to rub the clothes among each other and produce the cleansing action. The holes on the disc drain the water after the wash or rinse cycle is over.
Technically various motor technologies are used in these devices like DC series, and highly efficient BLDC, but in today’s time the most commonly used motor is still single-phase induction m/c, yes the same machine that runs the fans, water coolers, exhaust, small water pumps, etc.
For washing machine purposes we need to have various controlled characteristics:
- The motor must be producing high starting torque,
- it must reverse the direction of rotation after a fixed time period and,
- and must be efficient.
Out of all these points, fundamentally direction reversal is most important, as the clothes or water will be spilt out and very poor cleansing action will be obtained if the motor is operated in one direction. To understand how direction is reversed it is important to understand the principle of a single-phase motor.
This fan, for example, is a single-phase motor, and if we connect this motor in any way to the plug the rotation is always in one direction.
So how we obtain the reversal:
Full notes of 1-phase motor
These motors have a very simple structure and low maintenance. But has poor efficiency, around 50-60 %. They will slowly become obsolete in the coming 5-10 years.
For direction reversal as well as keeping the time, TIMER has a job to do. A normal semi-automatic WM uses a mechanical timer device to control the motor operation.
So let’s understand the timer first.
A timer as shown consist of four-terminal:
- Black: is the mains wire
- Brown: is the buzzer wire
- Yellow and red are two output wires each becomes the live terminal for half clock cycle with little delay in between.
So here is a demonstration circuit for the timer driving two bulbs alternatively.
Let us now use the timer to reverse the motion of our washing machine motor represented by this simple single-phase table fan same machine with lower power rating.
Idea: The direction of rotation of the motor can be reversed if the current in the two windings (main and auxiliary) are made to lag and lead each other in a cyclic way. This can be done if we connect the capacitor in series with the main winding and in the next cycle connect the capacitor with the auxiliary winding. This can be simply done if just exchange the live connection to the capacitor across the capacitor terminals. We also know the timer exchanges the live wire between its two terminals in a periodic way.
- Using the capacitor in winding 1, suppose motion to be clockwise:
2. Using the capacitor in the winding 2, the direction of rotation of the magnetic field is reversed:
3. Now just simply superimpose both of them by using the wash timer:
4. Finally, we obtain an electrical circuit for direction reversal:
And here is the actual demonstration model used in the tear-down event:
TOP LOAD AND FRONT LOAD:
A top-load machine like this one, the clothes and water are fed into a fixed vertically mounted wash cabin with agitator or impeller at the centre which is driven by a single-phase induction motor.
In case of a front-loaded machine, the clothes are fed into a horizontally mounted drum. In this case, the whole water-tight drum rotates back and forth, and the plastic paddles mounted on the drum slosh the clothes. Mostly the semi-automatic washing machines are top-load. And we have two options for the fully-automatic machine, they are available in both top and front load.
Which is better in case of a fully-automatic washing machine?
|Cheaper||More clothes can be washed in one wash cycle as a drum can be filled to the top.|
|Ergonomic||Less water consumption|
|Central agitator turns the clothes roughly||Gentle gravity aided wash|
|Clothes can be put inside in between the wash cycle||Rugged construction|
Here come the wonders of 21st century the ELECTRONICS. In general, any electrical systems when accompanied (or controlled) by electronics we get a real high efficient, flexible, magical and great user- friendly products. Fully Automatic gives you the elite experience of washing your clothes at a very low cost in terms of water, energy and effort used, and give ultra-clean fabrics. The whole machine operates by just selecting a few options and you finish washing clothes even without getting your hands wet.
The striking difference between the semi and fully automatic machines is the ability of a fully automatic machine to operate completely on its own once you have selected the fabric type. The embedded micro-controller operates various components in a controlled and synchronous way according to the already saved programs in its memory.
Look at the dashboard of a typical fully automatic washing machine (IFB, 7.5 Kg ):
You have a total of 10 different types of programs available and also you have the flexibility to set your own programs. The machine automatically set the wash, rinse and spin cycle (which includes the time and RPM), the amount of water and detergent, temperature of the water and even gives an option of delay time.
A TRAIL RUN:
Suppose you selected smart sense and pressed the start button then following is the routine the machine is subjected to go:
- To determine the time and RPM it necessary to know the amount of fabric in the machines, so the sensors first sense the weight and then accordingly set the timers.
- Then the micro-controller turns on the heating element and valve for inlet water and pours the detergent as required.
- The wash cycle begins, the flappers continuously rub the fabrics to remove stains and dust.
- Dirty water drains out.
- Rinse cycle begins and is repeated several times based on load.
- Then the tub is rotated at exceedingly high speed to force the water out through the holes on the inner drum.
- The machines give a buzzer sound indicating the wash is over.
The circuit design of fully automatic machines is beyond the scope of this discussion and for the writer also to understand and comprehend.
THE GREAT INDIAN MARKET:
Our country has shown a pretty healthy economic growth in the past 10-15 years.
- We were fifth-largest economy and also the fastest growing economy in 2018 (however current slowdown has dragged us down to 7th position in both categories),
- By this time the consumer durable has built a massive market of around 31.48 billion US dollar in 2017.
- We are the world’s second-largest smartphone market.
- We are the world’s third-largest television market.
Now, all the range of electrical and electronics products that you see in a typical household are broadly classified into two categories:
- WHITE GOODS: in other words Consumer appliances -These goods category include heavy-duty major equipment, for example, refrigerator, washing machine, induction cookers, microwave ovens, electric fans, etc.
- BROWN GOODS: Consumer electronics– Relatively small electronics goods like smartphones, TV, radio, digital camera, audio systems, etc.
Goods product like TV and refrigerator has reached inflexion point (saturation) with 75% and 30% Indian homes owning them, while products like AC and washing machine still hangs at relatively lower penetration of around 4% and 11% respectively. Whereas countries like China have AC and washing machine penetration up to 60% and 40%, clearly India still has a huge untapped potential for these goods.
The year 2018 saw a sale of 6.5 M units of Washing machine in India. So to analyse the Indian market for WM let us look at a few parameters: demand drivers, major manufacturers, technology type and new developments:
- Urban India:
Reason for such demand patterns is due to the high living standards and also the increasing disposable income of middle and upper-class society of first and second-tier cities. Reduced cost and elite technology has led for reduced replacement time also.
- Rural India:
Rural India does not show such great numbers but surely with increasing modernisation the consumer durable have now begun to be accepted as a necessity rather than a luxury. Here following opportunities are there:
- Electrification: Govt initiative to strengthen the rural electric system would surely play a detrimental role in future.
- Changing lifestyle: Rural India has also witnessed the pattern of changing lifestyles. There has been a significant increase in nuclear families, increase in awareness, and easier access to services, all of these makes a perfect cocktail for a consumer durable to gain some weight.
- Working women: Women in rural India have also begun stepping out which will generate the immediate need for laundry systems.
- Growing disposable income: The current slowdown has hit rural India the hardest- rural wage has stagnated for a while, FMCG have performed very poorly and overall demand has shown a negative slope, but still hopes of recovery from this disaster is there which will ultimately bring Indian economy back on track with more thrust.
- Multinational: The foreign players like South Korean LG and Samsung, Swedish Electrolux, Chinese Heir, Japanese Hitachi and Panasonic and American Whirlpool have already littered the India urban market with their cutting-edge, advanced smart-technology laundry system, which is more phantasmic in urban Indians.
- Indian players: They are equally capable of producing advanced washing machine but they all lag at brand popularity. The giants like Videocon and IFB have also shifted their focus on the rural market.
- Fully automatic: At a minimal increase in cost compared to semi-auto counterpart the fully automatic washing machine comes with far better improved and elegant user service. Thus fully-auto machines sales contribute significantly to the overall sale of washing machines.
- Semi-automatic: Having the advantage of low cost and simplicity they find their place in the rural region where current demands are not explosive like in urban regions.
New developments and updates:
- In October 2017 Flipkart launches its consumer appliances label called MARQ for selling products like ACs, WMs, etc.
Here comes the most interesting portion of the blog. In this globalised world, companies face great competition to win the consumer’s heart. And this is the engine fuel of modern innovation – to always keep one’s product a step ahead of others. Fortunately we the consumers get to see a modern marvel in this process. These days (2019) the fully automatic machines have become quite smart along with their conventional benefits of increasing the water economy, energy efficiency, child lock mechanism and user-friendly services, they now provide exciting features though at the cost of a significant amount of money.
To name a few:
- LG Twin-wash introduced in 2015 have both front load and top load for washing two different types of fabric at the same time. (60,0000 INR)
- Samsung Addwash can add fabric during wash cycles and gives the WiFi connectivity with your smartphone to operate your machine remotely and get the status. (46,000 INR)
- LG Signature provides features of extremely low noise and vibration, auto detergent dosing system and screen touch control panels.
- Finally, Panasonic sustainable maintainer which washes, drying and folding the clothes, however, the product was kept in a trade show at Berlin and is still to hit the market.
You can also explore some of the newest washing machines entering the market using the link below:
- (336) Panasonic presents a washing machine that folds your clothes and a fridge that comes when called – YouTube
PPT used in the presentation:
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