It is impossible to imagine a modern home without a huge number of different household appliances that need to be connected to the network. But not every wiring can withstand such a load. The old buildings were not designed for the use of such a volume of electronics, which is why accidents, power surges and other unpleasant situations occur. These electrical problems can easily destroy a refrigerator, TV, and even a washing machine. To prevent such accidents and ensure the protection of your equipment, you need to install the correct RCD. Which one exactly – let’s look at it in more detail.
When to install a difavtomat?
In what cases is it necessary to install a difavtomat? Let's say in your house or apartment there are a number of separate lines in different rooms for sockets and lighting 5,10,20 and maybe more. The ideal option in this case is to install difavtomats instead of simple circuit breakers on each line.
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Classification of washing machine drive overloads
Is your washing machine breaking plugs? In many cases, this is caused by incorrect operation of equipment and violation of the terms of its routine maintenance.
Washing machine overloaded
The user’s mentality of “why not put another towel in there” in practice does not speed up, but slows down the wash. When overloaded, the movement of things in the tank is limited and slowed down, so dirt removal is unsatisfactory.
Moreover, things do not receive enough washing powder. It is worth recalling that a detergent is a combination of surfactants that have the property of removing dirt, grease (and, by the way, germs) to the surface of the fabric. There, these harmful components become quite slippery, shake off with a cloth and pass into the soap solution. Unfortunately, this does not happen when the machine is overloaded.
Overload affects not only the items being washed, but also the mechanical design elements typical of a washing machine. Engine and tank bearings are especially affected. Additional loads for which they are not designed lead to jamming and stopping of the rotating drum, the replacement of which is expensive.
The unwritten law says - fill the washing machine tank no more than ¾ of the recommended volume, and operational failures will disappear by themselves. And use only those types of detergents that are recommended specifically for automatic washing!
Poor technical condition of the washer hose
The durability of the hose is limited to no more than five years of operation (it all depends on the intensity of washing). After this, it is unsafe to use the hose: it, as a rule, weakens and can become twisted under the influence of vibration of the machine drive. Let's take into account natural wear and tear and come to the conclusion: a leaky hose will allow an aqueous solution to pass into the body of the washing machine, after which the cause of the short circuit is obvious.
Motor overload
The characteristics of any type of electric motor for washing machines is a certain excess of the starting torque values in relation to the nominal one. However, when overloaded, the starting energy parameters increase sharply, which leads to extreme (“peak”) current consumption.
In general, washing machine motors are built to last and, with proper preventive maintenance, are designed to last the long life of the machine. Engine failure most often occurs for the following reasons:
- Dirt accumulation. Dirt can get into the engine starting switch, causing the moving contacts to close, or, conversely, preventing the contacts from closing reliably. In the first case, the engine does not start at all, but simply hums loudly and consumes an extremely high amount of power. If the circuit breaker does not trip, then operating the motor in this mode will burn its windings. In the second case, the high resistance connection causes a voltage drop that prevents the starting winding from receiving full voltage. Either way, if the situation continues long enough, the motor windings will burn out.
- Worn bearings. They increase the load on the engine and lead to its premature failure. This applies to any type of bearings - in the drive of the washing machine, in the tank or sliding bearings in the engine itself. A burnt out engine usually cannot be repaired.
- Washing machine drive belts. These are V-belts, similar to those used in some brands of cars. Even with normal use, they will wear out over time and require replacement. It is important to ensure the correct belt tension, since a belt that is too tight will put pressure on the engine plain bearings, causing damage.
Having identified the reasons, let's move on to the consequences.
Functioning and components of the RCD
What is the “protector” of household appliances made of? A standard machine consists of the following parts:
- transformer;
- protective housing;
- chain breaking mechanism;
- self-test sensor;
- electromagnetic cut-off device.
The RCD begins to operate when too much voltage is applied to the wires. In such conditions, the device forcibly opens the circuit and de-energizes the wiring. In addition, the machine will work if a bare wire comes into contact with water or a person.
Often, a residual current device saves not only equipment, but also human life.
Unlike outdated fuses of previous generations, the circuit breaker can be reused. It is not necessary to replace it with a new one after each drop.
Selecting the device type
When installing a difavtomat, you need to remember that they are divided into a number of types, depending on their operational capabilities:
- AC type. The device provides disconnection for residual alternating currents, both sudden and rising. It is the most universal type, suitable for all household devices.
- Type A. Provides disconnection for all types of alternating current and pulsating direct currents that may occur in a washing machine.
- Type F. The device will turn off all equipment that runs on alternating current, and with possible pulsations. It also guarantees detection of high-frequency faults up to 1 kHz.
- Type B. This type of automatic circuit breaker provides shutdown for residual alternating currents, pulsating and smoothly varying direct currents, regardless of whether they appear suddenly or with increasing intensity.
- Type B+. Necessary if it is necessary to provide shutdown for residual alternating currents, pulsating and smooth direct currents, constantly increasing or occurring suddenly. This also ensures that there are no unwanted trips and that high frequency faults up to 20 kHz are detected.
What kind of automatic machine should I put on the washing machine? The choice should be made taking into account the experimentally measured maximum power surges in the drive circuit. These measurements should be carried out by a qualified electrician, using modern and safe electrical measuring instruments, in particular clamp meters. Measurements are usually performed at least three times, in the most frequently repeated cases of machine drive shutdown.
The most commonly recommended standard sizes of automatic machines installed on washing machines are devices of types B or B+. They take spontaneous leakage into account and are effective if drives use DC consumers.
The sequence of operation of the differential machine is as follows. When current passes, the bimetallic plate heats up and breaks the contact between the circuit elements. If the nominal current values are restored, the plate cools down and turns on the circuit again.
Graph of gradual increase in current: Z – minimum zone, B – optimum zone; C – maximum zone
In addition to the type of automatic machine, a number of numerical criteria are also taken into account:
- Phase voltage in the house (easily set by the number of terminals on the front panel: three for a single-phase network, four for a three-phase network).
- Current rating. Automatic devices for household consumers belong to class C, and the number after this letter corresponds to the maximum current value. For example, a difavtomat of the C25 series is suitable for power consumption of no more than 25 A, C 16 - no more than 16 A, and so on. These indicators should be the same as for the existing RCD.
- Actual value of leakage current. To determine it, it is enough to touch any metal part of the unit with the contacts of the tester when the washing machine is connected. Acceptable values are 10...30 mA.
- Response time. Useful for loss of contact with the neutral wire, and cannot be higher than 0.3 s.
If all the characteristics of the device, which are necessarily in the passport, correspond to actual conditions, then the difavtomat will be selected correctly.
For example, usually the power of a washing machine is in the range of 2.5–3 kW (this value is in the passport), and then the current strength is calculated according to Ohm’s law, it will also be in the region of approximately 9 to 16 Amperes, based on this value the closest one is selected automatic in terms of power.
The wiring diagram for installing a two-pole automatic circuit breaker for a washing machine is shown in the figure:
Installing an outlet
After the wiring is laid along its entire length, you can install the socket. The sequence of actions is as follows.
- Installation of a socket box. To fix it, use the complete fasteners, but it wouldn’t hurt to additionally “seat” it with cold welding or sealant.
- The ends of the wire are inserted into the hole in the socket box.
- Unpack the socket and take out its inner part.
- The terminals are connected alternately: phase, neutral, ground. At the same time, you need to ensure that the ends of the wire are not too tight; do not forget that it is quite possible that the socket will have to be repaired.
- Using standard fasteners, the socket is securely fixed in the socket box. No play is allowed; it must “sit” motionless.
- Screw on the plastic cover.
After this, the wire is connected to the machine; of course, at the time of connection, the electricity in the apartment must be turned off.
Why does the washing machine knock out plugs?
It's all about a miniature circuit breaker, the operating principle of which was patented by Hugo Stotz in 1924. Such a switch is installed to protect the circuit from both overload and short circuits.
So, the main source of spontaneous shutdown of the washing machine is the excess of the actual power in the drive. Mechanical and domestic reasons for this have already been discussed. But there are also electrical factors. These include:
- Switching power supplies - found in all electronic devices to convert alternating current into direct current.
- Working chargers.
- USB sockets.
- Brushless drives.
They all have one thing in common: constant current and voltage. Under such conditions, the tendency for indicators to leak to the ground is more than likely. If this happens, the washing machine circuit must have a device that combines two functions: protecting equipment from overload and protecting people from electric shock, as well as insulation from burnout. Such a device is a two- or four-pole differential circuit breaker (hereinafter referred to as a differential circuit breaker).
The appearance and design of the difavtomat are presented respectively in the following figures.
