83.91.0.240.0000T Finder timerAsymmetrical flasher DC 24/240V

Finder 83.91.0.240.0000T Multifunction Timer Relay – 24–240 V AC/DC, 16 A, Railway Version, 4 Timing Functions

The Finder 83.91.0.240.0000T is a professional multifunction timer relay for railway and industrial automation applications. Part of the Finder 83 Series, this electronic timing relay provides precise, adjustable switching control for electrical circuits requiring repeated ON/OFF cycles, independently adjustable operating periods and reliable timed automation.

Featuring a 24–240 V AC/DC universal supply, a 16 A changeover contact and four selectable timing functions — LI, LE, PI and PE — the Finder 83.91.0.240.0000T offers a flexible solution for cyclic switching and asymmetric intermittent operation. Its adjustable timing range extends from 0.05 seconds to 10 days, making it suitable for both rapid repetitive operations and extended control sequences.

The T suffix identifies the railway-specific version, designed for applications involving vibration, mechanical shock and the environmental conditions associated with rolling stock. Its compact 22.5 mm-wide housing, screw terminal connections and standard 35 mm DIN rail mounting allow convenient integration into railway electrical cabinets, machinery panels and industrial automation systems.

Key Advantages

• Universal 24–240 V AC/DC supply supports a wide range of industrial and railway control voltages.
• Four selectable timing functions provide flexible cyclic and asymmetric intermittent switching.
• Independent ON and OFF timing control enables different energised and de-energised periods.
• 0.05 seconds to 10 days timing range accommodates short and extended switching cycles.
• 16 A changeover contact provides versatile switching for suitable electrical loads.
• Railway-specific T version is intended for demanding rolling stock applications.
• 22.5 mm-wide housing helps conserve control cabinet space.
• 35 mm DIN rail mounting simplifies installation alongside other electrical control components.
• Screw terminals provide conventional, secure electrical connections.
• IP20 protection rating for installation inside suitable electrical enclosures.
• Electronic timing control reduces the need for additional external timing circuitry.
• Selectable operating modes allow one device to perform several cyclic timing duties.
• Suitable for railway equipment, industrial machinery, ventilation, pumps and automated switching systems.

Key Features

• Finder 83 Series modular electronic timer.
• 83.91 asymmetric intermittent timing configuration.
• Railway-specific T variant.
• 24–240 V AC/DC nominal supply range.
• 50/60 Hz AC supply compatibility.
• Four timing functions: LI, LE, PI and PE.
• Asymmetric ON/OFF cycle control.
• Adjustable timing from 0.05 s to 10 days.
• One changeover output contact (1 CO / SPDT).
• 16 A rated output contact.
• Electromechanical relay output.
• AgNi contact material.
• Independent timing adjustment for the two phases of the operating cycle.
• Compact 22.5 mm module width.
• 35 mm DIN rail mounting.
• Screw terminal connections.
• IP20 enclosure protection rating.
• Railway environmental design referencing EN 50155, EN 61373 and EN 45545-2.

Four Selectable Timing Functions: LI, LE, PI and PE

The Finder 83.91.0.240.0000T provides four selectable functions for controlling repeated ON/OFF operations. The functions are designed for applications requiring adjustable cyclic timing, including sequences in which the relay remains energised for one period and de-energised for another.

LI – Asymmetric Flasher, ON First

The LI function provides repeated asymmetric switching with the output energised at the beginning of the cycle. The output remains energised for the selected ON period, then de-energises for the selected OFF period, repeating the sequence while the required supply and control conditions are maintained.

This function is useful where equipment must begin operating immediately and then alternate between active and inactive periods.

LE – Asymmetric Flasher, OFF First

The LE function provides repeated asymmetric switching with an initial OFF period. The relay waits for the selected delay before energising the output, then continues alternating between ON and OFF periods.

This mode is useful for applications requiring an initial waiting period before a repeated operating sequence begins.

PI – Asymmetric Pulse Timing

The PI function provides an asymmetric cyclic operating mode associated with pulse-initiated timing. It enables repeated switching sequences with independently adjustable timing periods, making it suitable for applications where the relationship between a control input and the switching cycle is important.

PE – Asymmetric Pause Timing

The PE function provides an asymmetric cyclic operating mode associated with pause-initiated timing. It is intended for control sequences requiring a defined initial pause and repeated timed switching.

Function selection note: The exact behaviour of LI, LE, PI and PE, including control-input triggering and reset conditions, should be checked against Finder's current 83.91 timing diagrams before commissioning. The function codes are not interchangeable.

How Asymmetric Intermittent Timing Works

An asymmetric timer relay allows the ON and OFF periods of a repeating cycle to be set independently. Unlike a symmetrical flasher, where both phases normally have the same duration, an asymmetric timer can keep a connected load energised for one period and de-energised for a different period.

For example, an industrial ventilation system may need to operate for a short interval before remaining inactive for a longer interval. Similarly, a cyclic lubrication system may require a brief operating period followed by an extended pause.

The Finder 83.91.0.240.0000T can perform this type of control through its selectable timing functions and adjustable time settings. Its single 16 A changeover contact allows a compatible load or control circuit to be switched according to the selected sequence.

The relay can therefore reduce the need for separate timing devices or complex external logic in straightforward cyclic control applications. Where a machine requires more advanced sequencing, feedback or safety-related monitoring, an appropriate PLC or control system may still be necessary.

Railway-Specific T Version for Rolling Stock Applications

The Finder 83.91.0.240.0000T is the railway-specific version of the Finder 83.91 multifunction timer. The T suffix identifies the variant intended for railway environments, where electrical equipment may be exposed to vibration, shock and changing operating conditions.

The railway version is associated with several important railway standards:

• EN 50155: Electronic equipment used on railway rolling stock, including relevant environmental and electrical operating requirements.
• EN 61373: Railway equipment testing for shock and vibration, with the railway variant referenced against Category 1 Class B.
• EN 45545-2: Fire protection requirements relating to materials and components used in railway vehicles.

These characteristics make the Finder 83.91.0.240.0000T suitable for consideration in railway electrical control cabinets and rolling stock auxiliary systems. The complete installation must still be assessed against the relevant project specification and applicable railway requirements.

DIN Rail Installation and Electrical Integration

The Finder 83.91.0.240.0000T is designed for mounting on a standard 35 mm DIN rail in accordance with EN 60715. Its 22.5 mm-wide modular housing allows installation alongside relays, circuit protection devices, power supplies and other automation components.

The device features screw terminal connections for the supply and output circuits. The universal 24–240 V AC/DC supply simplifies integration into equipment using different control voltages, provided the supply remains within the manufacturer's specified operating limits.

The relay provides one changeover output contact, allowing suitable normally open or normally closed switching arrangements. The output contact rating must be assessed against the connected load, particularly where motors, solenoids or other inductive loads are involved.

The timer's IP20 protection rating means it should be installed inside a suitable electrical enclosure. Electrical installation and commissioning should be undertaken by competent personnel following the manufacturer's wiring diagrams and applicable safety standards.

Typical Applications

• Railway rolling stock auxiliary control systems.
• Railway electrical equipment cabinets.
• Train ventilation and auxiliary equipment control.
• Industrial cyclic switching systems.
• Automated lubrication equipment.
• Ventilation and extraction fan timing.
• Industrial pumps requiring intermittent operation.
• Conveyor and material-handling automation.
• Packaging and processing machinery.
• Industrial process sequencing.
• Periodic equipment activation and deactivation.
• Machinery requiring independently adjustable ON and OFF times.
• Automated cleaning and flushing cycles.
• Industrial control panels requiring a wide-range AC/DC timer.
• Applications requiring a railway-specific 16 A multifunction timer relay.

Finder 83.91 Standard and Railway Timer Variants

The Finder 83.91 Series includes standard and railway-specific versions for asymmetric intermittent timing applications.

• Finder 83.91.0.240.0000: Standard multifunction asymmetric timer with 24–240 V AC/DC supply, four timing functions, one 16 A changeover contact and 22.5 mm DIN rail housing.
• Finder 83.91.0.240.0000T: Railway-specific version with the same core timing functionality and contact arrangement, intended for applications requiring the environmental characteristics associated with railway equipment.

When selecting a replacement, the exact manufacturer part number should be matched to the original equipment specification. The standard and railway variants should not be treated as interchangeable without confirming the relevant environmental and approval requirements.