Time relays
Time relays are devices that can implement delayed switching off and on processes. They are available as single-functional, dual-functional and multifunctional. These programmable devices are electronically controlled and can also perform off-delay functions. They are used to control machines on industrial automation lines. They are commonly used to build autonomous control systems in buildings and production halls. They reduce to the necessary minimum human supervision over the cycles of performed functions and are the basis for the construction of intelligent home systems.
Timers - application
The time relays are used to perform the time control functions of individual circuits. They find their application in automated control and management of current distribution in automation systems. Relays are mainly used in the control circuits of machines and technological lines. They work well in supervising the work of automated processes such as: air conditioning, ventilation, lighting and others. A time relay regulates logic functions as a function of time without the need to control a given process.
The time relay is mainly used as a programmable delay element. It allows you to operate in four operating modes:
delayed switching on,
delayed shutdown (return / waste delay),
actuation and return delay (impulse shift),
cyclic operation (pulse generator)
Industrial and home automation and home use time relays as a tool for measuring and implementing a given time program in power systems and automation systems. In the latter, it is used to control lighting, blinds or other devices that work cyclically.
Time relays are used in building automation, in various types of public utility facilities, such as shopping malls or airports, wherever there is control of heating circuits, doors, signaling, elevators and escalators.
How does a timer work?
Depending on the selected function (delayed switching on, delayed switching off, cyclical operation or delayed off), after the supply voltage is present, the system starts the timing of the working cycles. The output contact is closed and remains in this state until the supply voltage is cut off. Subsequent application of the supply voltage to the relay consequently leads to the system performing the delayed switching off function.
The most common function is delayed off. At the moment of appearance of the control impulse, the working contacts switch immediately, and at the same time the measuring of the set time is started. After closing the duty cycle, the contacts return to their original position again.
Characteristics and assembly
The standard, typical width of the relay for industrial applications is 17.5 mm, which enables precise layout design and ease of maintenance. The relays can be installed in control cabinets for plug-in sockets, on mounting plates or on a standard 35 mm rail. Screw connectors allow you to fix wires from 0.2 mm to 4.0 mm in diameter.
Modern types of time relays are distinguished by high repeatability and precision of the set operating times. They are characterized by high mechanical and electrical durability as well as resistance to low and high temperatures (from –20 ° C to + 60 ° C). Modern time relays have a wide range of time settings ranging from 0.1 s to 100 days. In conditions of increased risk of contamination, IP66 protection class relays are used.
