Circuit breakers are designed for installation in power distribution boards. Their main purpose is to compensate for voltage drops, as well as to turn off a certain section of the electrical network. Automatic machines, or VA for short, are designed to be installed at the beginning of an electrical circuit, at the entrance of a building, apartment, house.
Currently, there is a fairly large variety of circuit breakers on the market, which are designed not only to cut off high-value currents during voltage surges, but also from overloading a section of the electrical circuit, as well as from reduced network loads. By their appearance, all circuit breakers are divided into:
- selective;
- regulatory;
- high-speed.
The standard cut-off time for selective and standard automatic machines is within 0.02-0.1 sec. But for high-speed ones it is an order of magnitude higher, and reaches a value of 0.05 sec.
All machines have fasteners that allow them to be mounted in electrical boxes, shields, etc., which are equipped with a special mounting plate at the rear.
Installation of circuit breakers in the box is not difficult. To do this, you need to press it with the back against the mounting plate of the box and press it a little until a characteristic click. If you need to remove the machine, then you will need to pull the tab located on top of the machine.
The principle of operation of the circuit breaker
The mechanism of the machine is located inside the plastic case. In addition, there are also safety devices or releases , which can be two - electromagnetic and thermal. They are designed to cut off the electrical circuit.
The thermal release is a bimetallic plate, which, in the event of the passage of high currents, is straightened, opening the electrical circuit. This is a fairly slow breaker.
The electromagnetic release is a special coil that is designed for currents of a certain threshold value. In the event that this value exceeds the norm, the coil breaks the electrical circuit. Thanks to this property, an automatic machine with an electromagnetic release has a significantly short cut-off time.
Automatic sensitivity level
In modern machines, it is possible to turn off the voltage in two versions. The first one is fast. Thanks to the electromagnetic release, the machine trips when the voltage is exceeded by more than 140% (this is the threshold value for standard machines). If the excess voltage does not reach a predetermined level, then over time, due to overheating, the thermal release will trip.
Depending on the thermal characteristics of the release itself, the voltage, as well as the ambient temperature, the cut-off process can take several hours.
Polarity of circuit breakers
All modern automata are also divided depending on the poles. This means that the machine can have several electrical lines, which will be independent of one another, but united by one tripping mechanism. Currently, automata can have 1,2,3,4 poles.
Circuit breaker threshold current
Circuit breakers are also divided according to a certain threshold sensitivity. This allows you to cut off the voltage of the corresponding current strength from the network. Rated value breakers are manufactured and adjusted at the factory. The value of this indicator is written on the machine itself.
In private construction and everyday life, circuit breakers are used with the following current values: 3A, 6A, 10A, 16A, 25A, 32A, 40A, 63A, 100A, 160A. In addition, there are circuit breakers with increased performance - these are 1000A, 2600A, which are not used in private construction. This value shows us the total power of the consumers of the electrical circuit, which will be controlled by the given machine. In addition to the total power of the devices, it is also necessary to take into account the electrical wiring of the electrical circuit, sockets, switches, etc.
Types of modern circuit breakers
Currently, all machines are divided by manufacturers into several types, denoted by certain letters:
A- designed to work in circuits with semiconductor devices, as well as a fairly long length;
IN- are placed in the circuit of a general-purpose lighting system;
WITH- are installed in circuits of lighting systems, as well as in electrical installations with moderate starting currents. Such installations include motors, transformers.
D- are installed in the circuit of active-inductive load. In addition, these machines can also be installed on electric motors with large starting currents.
TO- machines designed for installation in networks with inductive loads.
Z- provide protection for electronic devices.
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