ABB (Asea Brown Boveri Ltd.) is a company whose key activities are electrical engineering, power engineering and information technology. Among other products, ABB manufactures low-voltage equipment, including differential automata, which are distinguished by impeccable quality and high reliability.
- 1 The appointment of abw ABAT
- 2 Classification of abavtomat ABB
- 3 The principle of operation of ABB difavtomat
- 4 How to choose difavtomat ABB?
The appointment of abw ABAT
ABB differential automatons provide all the necessary protections:
- a person from electric shock in case of contact with live parts of electrical equipment or when current leakage due to insulation damage of non-current-carrying parts due to high speed, less than 0.04 seconds;
- electrical appliances and equipment;
- electrical networks from short circuits and overloads.
Difavtomaty can be used in various conditions in any electrical networks, especially overloaded with equipment:
- for industrial use;
- in residential and small commercial buildings and premises;
- in administrative and industrial buildings and utilities;
- in catering;
- in the temporary power supply of construction sites, shops and stalls, garages and garden houses.
In AC power supply systems, ABB automatons with constant use of electrical devices and equipment can significantly increase the safety level of their use. These devices are triggered by overheating wiring and can prevent fire, which sometimes leads to a fire of current-carrying parts.
In electrical networks prolonged power surges are possible more than 265 V, caused by external noise, such as lightning discharges. The ABB differential automat provides protection against such jumps.
It is possible to select difavtomaty, designed for different operating currents and different levels of leakage current.
It is convenient to apply ABBs in cases when there is not enough space for installation of a separate RCD and a circuit breaker.
Classification of abavtomat ABB
ABB machines can be classified by the following features:
- by type of construction;
- in the form of differential current (AC, DC, pulsating DC);
- sensitivity, which is determined by the differential current protection operation (leakage);
- by response time, which shows how fast the trip will occur.
By type of construction are distinguished:
- without protection against overcurrents, which are denoted by VDT. These devices are sensitive only to leakage current; to protect against possible damage from overloads, they must be connected in series with a fuse or circuit breaker;
- connected to the circuit breaker BDT. On site combined with standard circuit breakers only once without dismantling attempts that will damage the entire device. When assembled, they possess both the characteristics of a differential current switch and the properties of a circuit breaker;
- New devices with built-in automatic circuit breaker AVDT are just differential automata.
The shape of the leakage current difavtomaty can be of three types:
- AC - for protection against differential current of sinusoidal form (only alternating current);
- A - to protect against pulsating DC or sinusoidal leakage current;
- B - to protect against leakage currents of all forms.
By sensitivity IΔn, difavtomaty are divided into:
- devices with low sensitivity greater than 30 mA, which provide protection in case of indirect contact in case of insulation failure;
- Devices with high sensitivity from 10 to 30 mA protect in case of direct contact (direct contact with live parts under voltage). They must be installed in rooms with high humiditywhere electrical appliances are used without step-down or isolation transformers;
- fireproof with sensitivity up to 500 mA.
The response time machines are:
- instant shutdown or high-speed;
- selective - delayed response. With their help, only the part of the equipment where the problem occurred is disabled. The response time in these devices is not adjustable and at low sensitivity values it is large and shortens to the minimum with its increase. It is better to put such automata at the input - fireproof with a sensitivity of at least 300 mA and a response delay, so that the diffs on the internal lines first work if necessary.
The principle of operation of ABB difavtomat
The ABB differential circuit breaker combines the functions of a circuit breaker and the properties of a residual current device (RCD). At the moment of occurrence of danger the electric power is automatically switched off A special “trigger window” in the differential mode allows you to immediately determine the cause of the emergency shutdown.
The design of the circuit breaker, which can be bipolar or quadrupole, has a special independent trip mechanism and rake reset using external mechanical action. As in a conventional circuit breaker, the tripping mechanism includes:
- electromagnetic release which serves to turn off the power line in the case of a short circuit, and almost instantly triggers at currents exceeding the normal consumption currents fourfold;
- thermal release triggered when overload occurs at lower currents that are not critical, but cause overheating in the network.
The differential protection module (MDZ) detects leakage current, for which the differential transformer and converts it into a mechanical effect, through which the electronic amplifier is used to reset switch.
The control circuit with a special “Test” button on the device case serves to check the health of the MDZ. When a button is pressed, a leakage current is intentionally created, to which a working automaton responds and turns off.
How to choose difavtomat ABB?
To choose the right differential machines for an apartment or an individual house, you need to know the technical characteristics of these devices and the main indicators of electrical networks.
- Phase network. ABB are single and three phase.
- Rated voltage. For three-phase machines, it is 380 V, and for single-phase machines - 220 V.
- Rated operating current. This is the current value at which the equipment will operate normally. Usually, consumption of installed household appliances on one branch is taken and a margin of 1.5–2 times is created.
- Characteristics of thermal and electromagnetic releasers. For household networks with a mixed load and moderate starting currents are used dify with letter C. In them, the minimum response current of the electromagnetic release is five times the rated current. The thermal release at the same current is triggered after 1.5 seconds. For example, for networks of sockets, an automaton with a characteristic of C16 (less often C25) is suitable, illumination is C6 or C10, and house-wide from C50 to C100.
- Rated current leakage. Typically, a difavtomat is used with a nominal for group networks — 30 mA, single outlets –10 mA, and at the entrance to a building or apartment — 100-300 mA.
- Type built-in RCD. For lines feeding TVs, computers, washing machines, it is advisable to use difavtomata with UZO type A, which react to leaks DC since the AC type that responds only to alternating leakage current can be ineffective.
Differential machines do not necessarily put on all lines. In the absence of space on the switchboard lighting lines can not be equipped with diffsby installing these devices only on common input (as a fire prevention measure) and socket lines.
If the networks do not incorporate a protective earth, protection against leakage currents in difavtomats may not be effective.
In the majority of residential buildings of the old construction network is overloaded with household appliances. Yes, and quite new buildings with modern engineering networks may not keep pace with the increasing number of household assistants with power supply. Therefore, in modern conditions the differential automaton ABB - this is an indispensable device, in difficult network operating conditions, which not only protects electrical appliances, but also is capable of saving human life.