Time relay on a din-rail: varieties and characteristics, installation, principle of operation

Household electrical panels house various modules to protect the human body from electric shock and wiring fire. But along with this, in distribution boxes, they are installed on a DIN rail and time relays. These are devices designed to optimize the operation of various devices by connecting or disconnecting them from electricity, according to established time intervals.

Purpose and constructions

The use of a control electronic device allows you to significantly save energy due to the fact that the supply of electricity to the devices connected to it occurs in an automated mode. By changing the relay settings, the consumer sets a certain time interval, during which various loads are connected to the voltage, and the rest of the range disabled. Thus, the time relay counts down a certain interval, and it does this in the cycle indicated for it.

The use of the timer has found widespread use For driving:

• lighting fixtures;
• water heating and heating systems;
• water irrigation devices;
• the work of advertising signs;
• opening and closing doors or windows;
• split system.

In addition, the relay is also used to create the effect of presence, which is used in the “smart home” complex. Several devices can be connected to it at the same time, however, their work will be synchronized.

The power source for the device can be either a built-in unit or an alternating voltage supplied from an industrial network of 220 volts. The installation of the timer is usually straightforward and can be easily done on your own. To start the device, the user will need to set the necessary intervals using the settings, connect the load and the power supply.

Device and types

Manufacturers can offer the consumer various designs of time devices. But at the same time, their purpose remains low: automatic switching on or off of electrical equipment at a precisely specified time and counting a specified interval.

All time relays according to the principle of operation are divided into five types:

1. With electromagnetic delay. They are used in direct current circuits. The operation of such a device is based on the property of the magnetic field to influence the armature of the inductor. With the growth of the main magnetic flux, inductance arises in the additional winding and a current is created that prevents the growth of the magnetic flux in the relay. This leads to a decrease in the movement time of the armature, as a result of which a turn-on delay occurs. If the current in the main turns stops, due to the residual induction, the armature will be held motionless for a certain period of time.
2. With pneumatic delay. The operation of such a device is based on mechanical phenomena, in particular, the use of a damper that controls mechanical vibrations. The response is slowed down by changing the diameter of the hole through which air enters. The structure includes a pneumatic relay and a timer with an anchor mechanism. Activation of the timer microswitch occurs due to the movement of the block with a frequency dependent on the air pressure.
3. With watch or escapement mechanism. The main parts of such a device are a spring and an electromagnet. When a current occurs in the coil, the relay is charged due to the magnetic field compressing the spring. The compression speed depends on the current, as soon as its stroke ends, the mechanism turns off the machine.
4. Motorized. Their design consists of a synchro-motor, a gearbox, a contact group and an electromagnet. With their help, a time delay of no more than 30 minutes is created. When the relay is turned on, voltage is supplied to the electromagnet and the motor. The latter begins to rotate the disks with cams acting on the contacts of the system. The deceleration time is set by the initial setting of the wheel position.
5. Electronic. All delays are implemented using microcontrollers or analog circuitry solutions. Using them, you can set time periods of any duration.

Instrument characteristics

The most interesting, from the point of view of users, are electronic time relays. This is due to their size, availability and time frames that can be installed on devices. So, in electromagnetic devices, the response time is from 0.07 to 0.11 seconds, pneumatic - less than 2 minutes, mechanical - from 0.1 to 20 seconds, motor - from one hour to 10-12 hours. In this case, the accuracy of work is often about 10%.

To the main technical characteristics of electronic devices include:

1. Rated voltage - devices are manufactured designed to operate in single-phase and three-phase networks.
2. Operating voltage drop - indicates the permissible deviations of the values ​​of the supply network from the nominal value. Usually, the devices remain operational in the range of 180-250 volts.
3. Power consumption - time devices belong to the low power consumption class.
4. The maximum current is the value that the changeover contact can withstand. This value is indicated separately for reactive and resistive loads.
5. The programming step is characterized by the value by which it will be possible to increase each subsequent value of the set time.
6. Lowest and longest time - indicates the range in which you can set the turn-on delay time.
7. Number of programs - indicates the number of cycles that are set independently of each other.
8. Wear resistance. It is specified separately for mechanical and electrical parts. It is indicated by the number of guaranteed on and off cycles of the relay.
9. Non-volatility is the time during which the programmed settings are not reset to zero in the device when the power supply is cut off.
10. Accuracy - characterized by the inaccuracy of the device. It is determined by the course of the clock during the day, it is indicated for an ambient temperature of 25 degrees.
11. Minimum and maximum operating temperature - the range in which the technical parameters of the device do not change.
12. Humidity - measured as a percentage and denotes an indicator at which the accuracy of the relay remains unchanged.

In addition to technical parameters, the relays are also characterized by quality indicators. These include: ease of use, size, mounting method. These parameters depend on the manufacturer. The most common are timers designed for mounting on a DIN rail and powered by a 220 volt network.

The principle of operation of the electronic type

The first electronic relays used transistors operating in a key mode in their circuitry. Then, they were replaced by integrated circuits, which were later replaced by microcontrollers.

The timer circuit is assembled on logic chips, a generator and an inverter.

In addition, a transistor signal amplifier must be used. The dwell time range is set by changing the parameters of the RC chain. By changing the charging time of the capacitor, different voltages are formed at the terminals of the microcircuit. As soon as a certain value is reached, its output is inverted and the relay is switched.

A significant advantage of time relays built on a microcontroller is the ability to change their program directly at the installation site. To do this, make changes to the program code using the device settings. Usually the device contains four buttons. One goes through the cycles, and the other three set the on time and the day of the week.

The operation of the microcircuit requires stable clock pulses, so a crystal oscillator is used in the device. During operation, the microcontroller counts these pulses and, depending on the programmed settings, gives a command to switch the relay. Usually such devices are equipped with an LCD screen and micrikas. By pressing the buttons, the work is configured, while all the necessary information is displayed in a convenient form on the screen.

Marking and connection

Each device manufactured in production is completed with a passport, which indicates the correct connection diagram. At the same time, on many devices this diagram is applied directly to their case, next to the marking.

By the designation on the product, you can determine its technical characteristics. Marking is carried out in the form of a set of letters and numbers, while the name of the brand is also indicated on the case. For example, in the label ETR4-11-A 24-240 V AC / DC letters and numbers indicate:

• ETR4 - model name;
• 11 - can work with both direct and alternating current;
• A - switching group consists of one contact;
• 24-240V - for operation, a 24 V DC power supply or 220 V AC power supply is required.

Mounting the product on a DIN rail is usually straightforward. Planks vary in appearance. There are three types of rails:

• omega - are the most widespread. They owe their name to the lateral section, the shape of which is similar to the letter Ʊ.
• WITH - used to install the terminal block.
• G - designed for hardware clamps.

The relay, designed for installation on a DIN rail, differs from other types only by the presence of a special mount at the back, which clearly fixes the device on the plate. To install the device on the plate, you will need to use a screwdriver. It is inserted into the hook of the mechanism, and with its help the clamp is pulled back. First, the upper mount is put on the rail, and then the lower part is pressed and the clamp is released. A characteristic click will confirm the correct installation.

In addition to the timer relay, other electrical protection modules are usually located on the DIN rail. The connection in the dashboard is as follows: the input line is connected to the circuit breakers, and from them it is connected to the relay.

The phase wire is taken from the output of the protective module, and the zero wire is taken from the neutral strip. The output contact of the relay is connected directly to the phase line of the load.

In fact, the connection diagram for all devices is carried out according to the principle: supplying power to the device and connecting the load through a group of connected contacts. For a single-phase network, there are two of them. Then, using buttons or rotary controls, the timer of the time relay is set to 220 V, that is, the time and the cycle of operation.

Manufacturers overview

The most demanded is the products of European manufacturers. This is due to the high quality control of their products and innovative developments with which they improve their devices. The leading brands include:

1. ABB. Swedish-Swiss company specializing in electrical products. Their products are easy to set up and reliable in operation. Operation indication is usually based on LEDs.
2. Legrand. The company from France is a recognized leader in Europe. It produces both analog and digital devices. Its models with a reserve of functioning can save the set settings for 100 hours when the electricity is turned off.
3. Schneider Electric. Another French company that produces all kinds of electrical equipment for both domestic and industrial use. Although its products are one of the most expensive, the manufacturer claims a service life of more than ten years for almost all of its models.
4. Hager. German company specializing in the production of low-voltage equipment. Their time relays have a high protection class and high quality LCD screens. At the same time, many models are equipped with plastic transparent covers with the possibility of installing a seal.

The products are slightly worse in quality, but also quite reliable and at a reasonable price are produced by: Eaton, ORBIS, Finder. Domestic companies can also compete with them: Relay and Automation, Eltekhnika, Energis.

The products of these manufacturers are always certified and have an attractive warranty period.