Rocker switch for a generator: the principle of operation and types, how to do it yourself

Since the advent of the first Volta battery, switching devices have remained one of the most important elements of any electrical circuit. Simple and complex, powerful and not so, manual and automatic, these devices can be found in almost any electric machine. One of the most important places in the range of switching devices is occupied by rocker switches. Due to their unique properties, these devices are practically indispensable for the creation of most complex electrical systems.

What is a rocker switch

What is an ordinary switch, perhaps everyone knows more or less familiar with electricity. In fact, this is an ordinary switch, only large and powerful. The handle is in one position - the chain is closed. In the other, it is open. If the switch switches one line, then the device is single-pole, and when you can switch several circuits at once with one handle, then the device is multi-pole.

Unlike a conventional knife switch, a changeover switch has additional contacts, thanks to which the device can not only turn on or off electrical equipment, but also switch. In one position of the handle, the middle bus of the switch is connected to the upper contacts, in the other - to the lower ones.

The most important thing about this design is that the top and bottom busbars cannot connect under any circumstances. This is what makes the device indispensable for switching equipment that does not allow connections between themselves during the switching process. Take a look at the diagram below:

In one position, the lamp is powered from the top battery according to the scheme, in the other - from the bottom. No matter how hard you try, you will not be able to connect the batteries together. What does it do? Suppose the polarity of the batteries is opposite, and instead of a light bulb, you used an electric motor.

In one position of the switch, the motor turns in one direction, in the other - in the opposite direction. But if you accidentally connect the batteries together, then serious problems begin - a short circuit. In the above example, you only run the risk of discharging the batteries, but if you switch more serious circuits - for example, voltages with different power lines, - then at the slightest mistake of the operator working with conventional switches, a serious accident is not to avoid. The changeover switch, due to its design, will not allow such an outrage, since you simply will not have erroneous options - "either-or".

The advantages of a toggle switch over a pair of conventional switches are obvious. But what if you just need to turn off the light bulb in the diagram above? Install an additional switch? This is not necessary at all, since there are three-position changeover switches. Unlike their two-position counterparts, they have one more position, the so-called intermediate, in which one source from the load is already disconnected, but the second is not yet connected.

Thus, using three-position switch you can not only make switching with one movement of your hand, but also disconnect the load from the source:

Advantages and disadvantages of circuit breakers

It remains to consider the advantages and disadvantages of these devices. The advantages include:

1. Visibility. The device usually has an open or semi-closed design, which means that its serviceability can be verified visually. Well, since you can clearly see the conductive knives and busbars, it will not be difficult to determine in what position the breaker is located.
2. Simple construction. Almost all such switches, including rocker switches, have an extremely simple design. They are very durable, easy to maintain, and usually low-skilled and inexpensive to repair.
3. High switching power / cost ratio. This is perhaps one of the main advantages of the devices. Some of these devices can switch currents of hundreds of amperes and are relatively inexpensive.

But switch-type switches also have disadvantages. Here they are:

1. Increased danger to the operator. Since most devices are open-ended, it is very easy to get energized if handled carelessly. Therefore, only qualified personnel are usually allowed to work with such switches, and the switch itself often fits in a closed cabinet or enclosure.
2. Irregular switching times. The switching speed of almost any switch depends only on the operator's response. When the blades are slowly shifted under load, a high-temperature arc can be “pulled” between the open contacts, which is equally dangerous for both the equipment and the operator *.

Arc suppression inserts, which are equipped with some types of switches, help to combat the arc only partially. That is why the overwhelming majority of electrical equipment manufacturers recommend switching using switch devices only after removing the load with intermediate circuit breakers.

Rocker switches

These devices have all the properties of toggle switches, but are devoid of the latter's drawbacks. Due to the special design of the switches, the energy of the operator's hand is not directly used for knives, and accumulates up to a certain value, and then makes a quick switch "Click". This significantly reduces switching times, reduces the possibility of arcing and enables on-load switching. In addition, working with switches is safer, since the devices are almost always closed. design, which means that even an unprepared person with zero knowledge of electrical engineering.

There is an opinion that switches are inferior to switches in terms of power, but this is not entirely true. There are devices that can switch the same hundreds of amperes, even under load. It's just that they are quite cumbersome in design and much more complicated than conventional knife switches. Like circuit breakers, switches can be three-position and multi-section.

Scope of application of knife switches and switches

From the foregoing, it is clear that such devices are designed to switch circuits, which under no circumstances should be connected to themselves. One of the striking examples is switching an object to a backup source. Suppose you are tired of constant power outages in a country house and have acquired a gas generator. The electricians turned off the lights, you switched to the generator. Turned on - again you power your house from the regular network. In words, everything is simple, but how to do it in practice? This is where the rocker switch will help you out. Take a look at the diagram below:

In one switch position the house is connected to the network, in the other - to the generator. Moreover, even if there is voltage both in the network and on the generator, there is no threat of switching - it is impossible to connect the network to the generator. Unfortunately, this scheme, although simple, is not entirely correct. Consider the steps that you must take when connecting the generator:

1. Disconnect the house from the regular power supply.
2. Start the generator and bring it to operating mode.
3. Connect the house to the generator.

You don't need to be seven spans in your forehead to understand that such a sequence of operations cannot be performed with an ordinary flip-flop device. You will either have to start the generator first, then switch, or switch sources and only then start the generator.

If the first option still works, then the second totally unacceptable for most household appliances. How will a refrigerator, for example, feel if, in the process of starting the gas generator, the supply voltage starts to rise from 0 to 220 V, and the frequency from 0 to 50 Hz? If you don't know, it will burn out.

This is where a three-position device will help you out. They disconnected the house from the network, started the generator, connected the house to the generator. And all with one pen, no additional devices, confusion and unnecessary costs.

Do-it-yourself rocker switch for a generator

What if you don't have a changeover switch at your disposal? You can do it yourself. More precisely, not to make, but to assemble from all well-known and widespread machines. To do this, it is enough to take two machines and fix them on one bar, having previously turned one upside down. In order for both devices to switch at the same time, you need to set on their sliders fixing bar (shown in orange). For this purpose, the sliders of all machines have special holes. The switch is ready. It remains to make a connection, which is practically no different from connecting a rocker switch.

Unfortunately, it turned out to be a two-position device, but on the other hand it has a built-in circuit breaker that will trip in the event of an overload or short circuit.

Of course, the real scheme for connecting a generator as a backup source will be somewhat more complicated than those given. above - in addition to the switch, you will need certain protection, grounding, metering devices, but there is nothing here either complex: