Impulse relay for lighting control

The light­ing sys­tem of a house or apart­ment should be designed in such a way that you do not have to wan­der in the dark for a long time to turn on or off the light. One option is to equip the sys­tem with auto­mat­ic motion or pres­ence sen­sors. With their help, the light will turn on as soon as you enter the room. But not every­one likes this kind of automa­tion. A more famil­iar way is to install switch­es near each entrance to a room or hall­way.

Impulse relay for lighting control

If there are only two inputs (for exam­ple, an entrance and an exit in a long cor­ri­dor), then the prob­lem is solved sim­ply: a pair of spe­cial switch­es, called bidi­rec­tion­al switch­es, are mount­ed near each of them. They work great — but only when exact­ly two con­trol points are required.

Impulse relay for lighting control

What if you need more? Say, in a liv­ing room with three door­ways, near each of which you need to mount a switch.
In such a sit­u­a­tion, it is advis­able to use the so-called impulse relay. The relay looks like a mod­u­lar cir­cuit break­er and is installed in the same way — in a shield, on a DIN rail. It has sev­er­al switch­ing con­nec­tors, on one side a cir­cuit with light­ing devices is con­nect­ed to one, and a cir­cuit with switch­es (push-but­tons) is con­nect­ed to the oth­er. Con­trol puls­es are applied to the relays from devices: a short press on the but­ton, and the load turns on, when touched again, it turns off. (This way you can turn on and off the light in the liv­ing room from any input.) The num­ber of push­but­ton switch­es con­nect­ed to the relay is unlim­it­ed. The ele­ments of the switch cir­cuit are inter­con­nect­ed by a two-wire cable of small cross sec­tion (twist­ed pair).

Relay options

Like almost any elec­tri­cal equip­ment, impulse relays dif­fer in max­i­mum rat­ed cur­rent (usu­al­ly house­hold ones are rat­ed at 16 A) and sup­ply volt­age (12, 24 and 230 V). In addi­tion to stan­dard relays, low-noise ones are pro­duced that do not emit char­ac­ter­is­tic clicks when switch­ing. We also note relays with a dis­con­nec­tion delay (from 5 to 60 min­utes), dis­con­nect­ing the load after a set delay time. They are usu­al­ly used to auto­mat­i­cal­ly turn off the light (in stair­wells, out­doors, etc.) or ven­ti­la­tion, for exam­ple, in bath­rooms.

This design has many advan­tages. It is quite sim­ple to install and does not require the use of expen­sive cables. As for the cost of the relay, today mod­ules from Legrand, ABB, Schnei­der Elec­tric or sim­i­lar man­u­fac­tur­ers can be pur­chased for 20–30$.

Impulse relay for lighting control

In addi­tion, when using impulse relays and illu­mi­nat­ed push­but­tons, LED lamps do not flick­er in the off posi­tion, which is typ­i­cal for con­ven­tion­al illu­mi­nat­ed switch­es. The dis­ad­van­tages of the sys­tem include a lim­it­ed num­ber of design options for the switch-but­ton. Some dif­fi­cul­ties also arise when using a large num­ber (more than five pieces) of switch­es with built-in light­ing, so the impulse relay is sup­ple­ment­ed with the so-called com­pen­sa­tion mod­ule. It pre­vents false trip­ping of the relay.

If the electrical panel in the house is located next to the rest rooms, it is better to use low-noise impulse relays that will not disturb the peace of your family members

Impulse relay for lighting control

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