Time relay - construction, principle of operation, types

The control of the power supply to industrial machinery, lighting, heating and ventilation systems and many other devices can be carried out automatically. By using time relays in electrical installations, selected circuits can be switched on or off at pre-programmed intervals. They are extremely functional. If you are curious about their construction and principle of operation, in this article you will find the most important related information. We describe the technical aspects and also tell you how to read the diagrams and symbols on the housing - enjoy the read!

How are time relays constructed and where are they used?

Before going on to explain how a time relay works, here is a general diagram of its construction and basic applications. These devices are usually suitable for DIN rail mounting (in control cabinets). They have a plastic housing, which, for some models, is characterised by increased tightness - this is described by the IP symbol, followed by the digits indicating the protection level.

Considering the basic elements that make up a time relay (https://www.relpol.pl/en/Products/Time-relays), its structure will vary depending on the version, but it always specifies:

• input and output circuit
• the module responsible for time programming. Very often the module is set using dials (described by symbols), but there are also very precise (up to 0.1 s) modules set electonically https://relpol.pl/en/Products/Time-relays/Modular-time-relays/Time-relays-MT-W.
• relay or triac outputs based on semiconductor relays
• LEDs indicating the operating status of the device - the pattern of their operation may be different in each model.

Time relays - where are they used?

Given their versatility of application, time relays are commonly used in industrial plants, public facilities, housing associations or private buildings, among others. They can be connected to the circuit supplying any electrical device to be started or switched off at a specific time or sequence. They are available in a number of versions, differing in function, construction and connection scheme.

How does a time relay work and what types are there?

Whichever time relay you equip yourself with, its operating principle will be identical. As you already know from the description of its construction, there are knobs with the appropriate symbols on them, or electronic buttons for setting the appropriate function and mode of operation of the relay. Using these, all you need to do is set the preferred function and the device will be ready to operate.

It is important that the timing relays are properly selected to suit the needs and conditions in which they will operate. There are many types of them, but there are 3 main, classifying features according to which they can be:

• electromagnetic (contact control) or solid-state (solid-state relay is the actuator)
• single, double or multifunctional
• for dedicated voltages, e.g. 230 V AC or a wide range from 12...240 V AC/DC

Programming diagram for time relay

Each such device comes with an electronic manual https://www.relpol.pl/en/Download/Instructions/Time-Relays, in which you will find a diagram showing how to programme the time relay. This is usually based on electronic push-button control, or 3 dials - one is used to select the function and the other two are responsible for setting and time range. In the case of a relay with the possibility of setting two independent times, e.g. in the RPC-TIP relay... https://www.relpol.pl/en/Products/Time-relays/Modular-time-relays/Time-relays-RPC-1IP, there are four rotary knobs and each of the two times is set separately. Depending on the model, the time setting can range from just a few milliseconds to many days.

All time relays can perform various functions, each of which is described by a special symbol. There may be many of these, depending on the application of the device, e.g::

• E – załączenie z opóźnieniem
• Bp – cykliczna praca symetryczna następująca od przerwie
• R – opóźnione wyłączanie
• E - switching on with delay
  Bp - symmetrical cyclic operation following a break
  R - delayed switch-off

A detailed description of these designations, together with the principle of operation and a wiring diagram, can always be found in the instruction manual supplied with the unit. https://www.relpol.pl/en/Download/Time-functions

High quality and functional time relays in the offer of our company Relpol!

Now you know how a time relay works, you know its construction and its application. If you want to use it in your electrical installation, use the offer of our company - Relpol (https://www.relpol.pl/) - we invite you to contact us. We sell many types of these devices, all of which meet the highest quality standards. The multitude of models makes it easy to match them to your needs in terms of functionality. Each one comes with a manual describing the wiring diagram and symbols on the housing, making them very easy to use!