Pulse relay connection for lighting control

With modern wiring, radically new elements are often used. One of these is a pulse relay (IR). The mechanism makes it easy to control lighting from several places at once, which is especially convenient for long extended rooms or a courtyard. You can also set a simple single-key switch for several lighting fixtures in the room at once.

The device and principle of operation of IR

Structurally, relays consist of such blocks:

• Coil. It is a thin copper wire that is wound around non-magnetic material that does not allow electricity to pass through. It can be a fabric or varnish coating.
• Core. It comes into motion at the moment the current passes through the winding of the coil due to the fact that it contains iron.
• Anchor (movable). It has the form of a plate that affects the closing contacts.
• Circuit status switch. It is also called a contact system.

The effect of IR is completely based on such a physical phenomenon as electromagnetic force. The principle of operation of the relay step by step:

• When the IR is turned on, current flows through the core of the coil.
• As a result, the core, attracting it, simultaneously brings into operation all the power contacts. Moreover, they are normally open or closed.

IR is a kind of mechanism that breaks or closes an electrical circuit. Sometimes, for more accurate operation, a resistor, semiconductor diode or capacitor is connected to the device.

Varieties of IR

All lighting control relays are divided into two groups:

• Electromechanical. The mechanism is responsible for the operation of the device.
• Electronic. The brain of IR is a printed circuit board equipped with a microcontroller.

All types of pulse relays are characterized by such signs:

• Output current - its maximum value for the clamps of the coil at the time of the output of the armature.
• Retraction current. Its smaller value when the working anchor returns to its primary position.
• Return coefficient. The ratio of output currents to the current retraction.
• The magnitude of the response. This is the optimal value of the input signal to which the pulse switch responds.
• Set point. The response parameter of the mechanism within certain limits specified in the relay.
• Rated values All indicators of current, voltage, ensuring the operation of the device.
• Response time. The duration of the response to a given command. May vary from 0.0001 sec. up to 1 min

It is electromechanical devices that are most popular.

Relay wiring diagram with one normally open contact

The relay switch can be connected in one of the simplest schemes. This greatly facilitates the work of the wizard. The main thing to remember: the switch responsible for the lighting process should only be in the open state. This is due to the fact that it has an opening spring, which instantly operates at the moment of pressing the button. As a result, the circuit closes elsewhere.

The connection is performed as follows:

• one contact output is brought to phase;
• the other goes to zero;
• a neutral wire is pulled to each lamp involved in the lighting.

It is forbidden to exceed the permissible number of switches indicated in the relay passport. If you ignore this, the device can often operate false.

So that the device does not spark at the time of switching on, it is advisable to install a capacitor.After completing the installation of a pulse relay for lighting control, make a full isolation of contacts. To do this, it is better to use special shrink cambric.

Advantages and disadvantages

If we consider the pros and cons of pulse relays, you need to do this for each type separately. Electromechanical switches have the following advantages:

• Favorable cost in comparison with electronic.
• Powerful 5 kV insulation between the contact group and the coil of the winding.
• A weak voltage drop on the switched off contacts, which means a low percentage of heating of the device.
• Inertia to overvoltage surges and interference during lightning.
• The ability to control the line with an optimal load of up to 0.4 kV.

Of the disadvantages of electromechanical pulsed light switches note:

• Radio interference occurs when the circuit is turned on and off. To avoid this effect, you need to resort to shielding, or increase the distance from the relay to devices exposed to third-party waves.
• Relatively quick wear of the switch at high voltages and currents. It includes deformation of springs, oxidation of contacts.
• Longer response time than circuit breakers with a circuit board.

For electronic pass-through relays, the following advantages are characteristic:

• excellent switching speed;
• good security for the wizard and users;
• wide selection of models;
• reasonable cost;
• the presence of indicators that inform about the operation mode of the device;
• silent operation;
• extended range of features.

Electronic relays can be mounted in different ways - on the DIN rails of the flap or directly into the socket.

Of the minuses of the devices emit:

• severe overheating to a critical point under the condition of switching a large current;
• disruption of operation at the slightest network failure;
• frequent causeless “glitches” with impulses;
• the presence of high resistance when closed;
• relay shutdown if a short-term voltage drop occurs in the network;
• the ability to operate certain types of devices only with direct current;
• slow passage of current reverse to the normal direction due to the characteristics of the semiconductor circuit.

Despite the fact that electronic controlled switches have a larger number of disadvantages, devices are constantly being improved and improved. Therefore, it is possible that they will soon supplant the electromechanical relays completely.

How to avoid errors at 3 levels when connecting IR to an electrical panel

For a master without experience, the task of connecting a relay becomes quite difficult. The specialist is often lost in determining the sequence of connecting elements with each other. Moreover, the work will be the more difficult the more used switches. The easiest way is to install the relay to a single-key element.

Actually, the work is not as complicated as it seems. The main thing is to comply with all installation requirements, then the number of relay control buttons can be unlimited.

Under the condition of three connection levels, step-by-step installation should be performed.

• RCD installation for lighting protection.
• Installation of the machine for several groups of backlight sources at once.
• Installation of a pulse relay.

RCDs are assembled according to a typical circuit for a switchboard and meter. Then it is worth installing and connecting the circuit breakers for individual groups. They work on control cables and all fixtures. Then mount the relay. And you need to remember that they put their own IR on a separate group of lighting devices.

If you do all the work in the above sequence, you can control the light sources inside the same room using a single-key circuit breaker, instead of a multi-key. This allows the user not to get confused in the buttons.

When working with an electric meter, IR and other network elements, it is advisable to do everything in rubberized gloves and be sure to disconnect the line.