Modular relays

Time-delay relays and timers are modular DIN-rail devices that provide electromechanical or electronic timing functions in an electrical panel. They can delay the making or breaking of a circuit, generate periodic cycles, or produce a timed pulse, with setting ranges from one second to several hours depending on the reference. Compliance with the IEC 61810 standard guarantees the reliability of the base relays, while CE marking confirms their placing on the European market.

Timing functions and setting ranges of time-delay relays

Operating modes available for modular timers

Time-delay relays offer four main functions: on-delay timing delays the output circuit being energised, off-delay timing keeps the supply on after the control signal is removed, cyclic mode generates a periodic succession of active and inactive phases, and pulse mode delivers a fixed-duration pulse regardless of how long the control signal is applied. Our installation experience confirms that the choice of mode directly determines suitability for the target application.

Setting ranges and timing precision

Setting ranges cover multiple scales, from a few seconds up to several hours depending on the reference selected. This modularity allows both fast sequencing tasks and night-time ventilation cycles or extended-duration circulation lighting timers to be addressed. Our commissioning tests show that a well-calibrated range avoids rough settings and guarantees cycle repeatability.

Panel integration and constructive characteristics

DIN-rail mounting and installation compatibility

The polyamide housing and standard DIN-rail mounting provide direct integration into any existing electrical panel without mechanical adaptation. This standardised modular format makes it easy to replace a faulty time-delay relay or add a timer during a panel extension. Our standard practice favours this type of product for renovations where available space is limited.

Dry-contact output and control of downstream circuits

The dry-contact output can control a power contactor, an auxiliary relay or directly a low-consumption circuit without any electrical interaction with the control section. This galvanic isolation between the timing circuit and the power circuit protects the setting electronics and simplifies wiring. In the field, we find that this architecture reduces failures linked to inductive-load transients.

Typical applications and field feedback on modular timers

Automation of circulation lighting and access lighting

Circulation-lighting timers equip stairwells, underground car parks and building corridors to limit energy consumption while maintaining user safety. Off-delay timing is particularly well suited to these uses, as it keeps the lighting on after someone has passed through. Feedback from installers confirms that this principle avoids complex configurations with multiple presence detectors.

Ventilation timing and control sequencing

Intermittent ventilation of wet rooms, or the staggered start-up of several motors on the same line, avoids simultaneous inrush currents. Cyclic mode suits forced-ventilation systems at regular intervals, while on-delay timing allows equipment activation to be staggered. We find that this approach extends the service life of electrical components by reducing start-up thermal stress.

Frequently asked questions

What is the difference between an on-delay and an off-delay time-delay relay?

An on-delay time-delay relay delays the output circuit being energised after the control voltage is applied, whereas an off-delay time-delay relay keeps the circuit energised for the set duration after the control signal disappears. The former suits delayed start-ups, the latter suits maintaining a function after an action.

Can an electromechanical time-delay relay be replaced with an electronic model on the same DIN rail?

Yes, most electronic time-delay relays keep the same modular width and the same DIN rail as electromechanical versions. What needs checking is coil-voltage compatibility and whether the contact rating suits the existing load circuit.

Which standard applies specifically to the base relays used in modular timers?

The IEC 61810 standard defines the fundamental requirements for basic electromechanical relays, including their electrical, mechanical and environmental characteristics. It is the reference for assessing the reliability and contact life of time-delay relays and timers.

How should the timing range for a stairwell lighting timer be chosen?

The timing duration for stairwell lighting is determined based on the estimated travel time plus a safety margin, generally between 30 seconds and 5 minutes depending on the height of the building. A setting range that is too wide reduces fine-tuning precision, while a range that is too narrow limits the possibilities for adjustment.