Dif automatic ABB 16a: the basics of work, control of differential current, connection and marking

The installation of protection devices is an indispensable element of the safe use of electrical networks. As such, circuit breakers and residual current devices (RCDs) are used. The device combining these two types of devices is called a differential machine. For protection, it is extremely important to use the products of well-known companies, for example, the ABB 16A diff automatic machine. This approach will reliably protect you in the event of an emergency situation.

History of the company

The year of foundation of the ABB company is considered to be 1988. Formed by the union of the Swedish company ASEA and the Swiss company Brown, Boveri & Cie, the company directed all its production to the manufacture of electrical products. At the beginning of the 90s, ABB began to occupy a leading position in the countries of Eastern Europe and Asia. In 2000, Asea Brown Boveri Ltd was recognized for the third time as the most promising company in the Dow - Jones index and conquers a share of the US market for the production of electrical products.

The main directions in the development of the company are: production of electrical equipment, automation of processes, production of protection systems. Since 2011, following the acquisition of the Swiss company Newave, the company has added the production and service of uninterruptible power supplies to its production.

Until the early 1980s, circuit breakers were used to protect electrical lines from fire. Their purpose was to disconnect a section of the circuit when high current values ​​appeared on it, caused by a short circuit (SC) or a malfunction in the load. Together with him, in the 90s, they began to use an RCD, which protected a living organism from the harmful effects of electric current in the event of a leak.

The combination of these two protection devices in one case led to the emergence of a differential machine. The manufacture of a device capable of providing comprehensive protection was not spared by the Swiss company, which launched the production of ABB differential automatic machines.

Principle of operation

Combining devices in one housing allows you to reduce the space in the electrical panel while maintaining all protection capabilities. At the same time, ensuring ease of connection, all devices manufactured under the ABB trademark are made of non-combustible and durable plastic. Structurally the device consists of the following parts:

• release;
• control lever;
• arc suppression chamber;
• magnetoelectric relay;
• differential transformer;
• switching terminals:
• device testing circuit.

The differential automatic device consists of two simultaneously operating parts in the RCD and circuit breaker modes. The task of the first part is to monitor the differential current, to identify the leakage current. The second part serves to mechanically break the power line when large currents appear on it.

The main element of the first part is a differential transformer consisting of a toroidal core with two windings. The current, flowing through the windings in different directions, creates oppositely directed magnetic fluxes of equal magnitude in them. As a result, the resulting magnetic field in the core is zero. In fact, this means that the phase conductor current is equal to the neutral conductor current.

If a differential current occurs on the line, then more current begins to flow through the phase conductor than through the neutral conductor. The balance of magnetic fluxes is disturbed and under the influence of the field, an electromotive force (EMF) is induced in the secondary winding. When an EMF occurs, a current appears that acts on the relay. Power is removed from the solenoid, and it opens the contacts to which the load is connected.

To check the differential part of the device, a button is displayed on the front surface, which simulates the appearance of a leakage current. This button is labeled "Test". If you press it and the device is working properly, then the electrical circuit will break.

The second part works on the principle of changing the shape of a bimetallic strip under the influence of heat. The current enters it through the solenoid coil. The plate consists of two thin pressed metals with different coefficients of linear expansion. The plate and the solenoid together form an assembly called a release.

Thus, when large currents arise, the bimetallic plate heats up and begins to bend, thereby breaking the contact. Accordingly, breaking the electrical circuit. The current at which the plate breaks the contact is set at the ABB factory.

If the contact breaks, a spark is generated that can damage the internal components. To avoid this, an arc suppression chamber is used, consisting of parallel plates, in which the arc is scattered.

Varieties and recommendations

The main classification of ABB protection devices is based on the type of control. It can be with an independent power source and does not require it. Devices with an additional power supply allow the load to be automatically connected to the power line when service is restored. Besides, dif automata are divided:

1. By type of registration - electromechanical and electronic. The difference is that electromechanical ones do not require additional power supply, since the voltage for its operation is taken from the industrial network. The transformer, in order to achieve the magnitude of the current that provides the required voltage, is made large, respectively, and the device itself is larger than the electronic one. The electronic device is supplemented with an amplifier for the signal, increasing the value of the detected leakage current.
2. By type of mounting - stationary and portable.
3. By the number of poles - two-pole and four-pole. Each pole is an input for a power line. The amount depends on the type of network.
4. In terms of resistance to impulse voltage - whether or not they react to an impulse signal.

At the same time, some series, for example, DS201 and DS202, include an indicator of the position of the main power contacts. If the device is triggered in the leakage current protection mode, the special red window will change color and turn green, regardless of the position of the switch. This allows you to always correctly determine the state of the device, regardless of how it is located on the din - rail.

Parameters and characteristics

The technical characteristics of the differential circuit breakers combine all the parameters of circuit breakers and RCDs. Moreover, they are of the selective type and non-selective. The selective type is used as an input device for monitoring the entire power line. From the main characteristics of the diff. automatic machines ABB highlight the following:

1. Rated current. The magnitude of the current that passes through the device does not cause it to operate. They are produced in a strictly defined value from 1 to 63 amperes. For example, diff. automatic machine for 16 A series DS951B-16.
2. Time-current characteristic. The ratio of the actual strength of the current passed through the machine to its operating value is characterized. Indicates the degree of sensitivity of the automatic machine.
3. Differential current. Indicates the magnitude of the leakage current that triggers the protection of the device. Has standard ratings: 10 mA, 30 mA, 100 mA, 300 mA, 500 mA.
4. Working voltage. A value that ensures uninterrupted operation of the device.
5. Breaking value. The current value that appears on the line and does not lead to damage to the differential. machine. Standard values ​​3000 A, 4500 A, 6000 A, 10000 A.
6. Current limiting class. It is determined by the speed of the device's reaction to the occurrence of an emergency.
7. Protection control type. Electromechanical or electronic.
8. Differential protection type. Depends on what type of leakage current the machine works with. The AC type works with a sinusoidal signal. Type A with sinusoidal and constant signal. Type B for protection against leakage currents of all forms.
9. Temperature Range. The temperature range at which the device will meet its operating characteristics.

Of all the characteristics for home use, first of all, you should pay attention to the sensitivity and power of the device. Low sensitivity over 30 mA provides protection against indirect contact and insulation damage. Devices with a sensitivity of 500 mA are considered fire-fighting, and with a value of 100-300 mA they are used as an introductory machine. Automatic devices with a value of 30 mA are used as group devices, and for individual sockets with 10 mA.

The power is selected according to the rated current of the dif. machine. It characterizes the value that the electrical wiring withstands without damage. It is determined by the cross-section of the wire and the material from which it is made. In houses, the most popular machines for use with a value of 16 A, they are used to protect a wire with a cross section of 1.5 m². Circuit breakers rated 25 A, 32 A are used in apartments as introductory ones.

Connecting the machine

Dif. The ABB machine is mounted in the dashboard on a din rail. The device is installed in a break in the electrical line by clamping the electrical wires in a screw clamp. Connection recommendation from ABB as follows:

1. The differential machine is installed above the power line, on a din rail, with the possibility of free access to it.
2. The input line is connected to the upper terminals of the machine, and the output line is connected from the bottom.
3. The stationary part of the control lever must be on top, that is, the device is turned off by switching the lever from top to bottom.
4. The wires are connected in series. It is forbidden to connect cables of different circuits.
5. Only the wires of the circuit that is being protected are connected to the device. Neutral wires of different circuits must not be combined.
6. After completing the installation, the operability is checked by pressing the control button.

The devices are designed to operate on lines with which an earthing bus is used. But in its absence, work is also possible. The difference is that if there is grounding, diff. the machine will instantly operate when an earth leakage current occurs. And in the absence of grounding contacts for the device to operate, you will need to touch the damaged area.

In this case, a differential current will arise through the organ of a living organism, and the automaton will work. The time of exposure to current before the machine is triggered is small fractions of a second, and is not dangerous for humans.

Marking and designation

The marking of the device will help you see all the main technical parameters, in spite of the description. It helps to distinguish a differential device from an RCD. For this, an electrical circuit is indicated on the body of the device, containing both a release and a transformer.

The operating current is applied without the measurement value in amperes after the letter indicating the type of time-current characteristic, for example, C16. The letter N denotes a contact for connecting a neutral wire. An icon of the type IP 24 indicates the degree of protection, and in the rectangle there is a number corresponding to the switching capacity at short circuit.

For example, this is the type of a differential machine designed for a rated current of 16 A: ABB DS951 1P + N, C 16A, 30mA, type A134. It can be decrypted as follows:

• ABB DS951 - model range;
• 1P + N - number of poles;
• C - signal characteristic;
• 30mA - differential current to ground;
• 16A - rated current;
• type А134 - for alternating voltage. Breaking capacity 6 kA.

Differential automatic machines from ABB are distinguished by their high housing quality, long service life and high mechanical strength. The quality of the devices is confirmed by certificates and the warranty period given by the manufacturer for its products. The speed of the residual current circuit breakers allows the power to be cut off instantly, which guarantees the protection and safety of consumers.