Why Choose the Finder 7S.34.8.120.4220 Safety Relay?
The Finder 7S.34.8.120.4220 is a professional 120 V AC safety relay module with forcibly guided contacts, designed for industrial machinery, automation systems and safety-related electrical control circuits. Part of the Finder 7S Series, this four-pole electromechanical relay features a 2 normally open (NO) + 2 normally closed (NC) contact arrangement, providing reliable switching and contact-state monitoring within appropriately designed safety systems.
Featuring Class A forcibly guided contacts in accordance with EN 61810-3, the Finder 7S.34.8.120.4220 enables external monitoring circuits to detect specified contact failures, including welded contacts. Its mechanically linked contact arrangement is particularly useful in applications where the switching state of a relay must be monitored as part of a machine safety function.
With a 120 V AC nominal coil, 6 A rated contact current, 250 V AC nominal switching voltage and silver tin oxide (AgSnO) contacts, this relay provides a practical switching solution for industrial control applications. Its 22.5 mm-wide DIN rail housing, screw terminals and integrated LED coil indication make it suitable for installation in electrical control cabinets and machinery panels.
Key Advantages
- 120 V AC coil for compatible industrial AC control supplies.
- 2 NO + 2 NC contact configuration provides separate switching and monitoring contacts.
- Class A forcibly guided contacts support fault detection in safety-related control systems.
- 6 A rated contact current for suitable industrial control loads.
- 250 V AC nominal switching voltage for compatible electrical applications.
- Silver tin oxide contact material provides dependable electromechanical switching performance.
- Integrated LED coil status indicator simplifies commissioning and troubleshooting.
- Screw terminal connections provide secure and familiar control panel wiring.
- 22.5 mm-wide housing helps conserve valuable DIN rail space.
- 35 mm DIN rail mounting enables straightforward installation in industrial cabinets.
- IP20 protection rating for installation within suitable electrical enclosures.
- Suitable for integration into machinery safety and monitored switching circuits.
- Supports applications designed to achieve SIL 2 or PL d, subject to complete system assessment and validation.
Key Features
- Finder 7S Series modular safety relay.
- Four-pole electromechanical relay with forcibly guided contacts.
- 2 normally open + 2 normally closed contacts.
- Class A contact guidance according to EN 61810-3.
- 120 V AC nominal coil voltage.
- 50/60 Hz AC supply operation.
- 6 A rated contact current.
- 250 V AC rated switching voltage.
- 1,500 VA AC-1 switching capacity.
- Silver tin oxide (AgSnO) contact material.
- Approximately 1.1 VA nominal coil consumption.
- Integrated LED indication of coil energisation.
- Non-latching electromechanical operation.
- Screw terminal connections.
- 35 mm DIN rail mounting in accordance with EN 60715.
- 22.5 mm module width.
- −40 to +70 °C operating temperature range.
- IP20 enclosure protection rating.
- Designed for industrial machinery, monitored relay circuits and safety-related automation applications.
Technical Specifications
- Manufacturer: Finder
- Series: 7S
- Manufacturer part number: 7S.34.8.120.4220
- Alternative part number: 7S3481204220
- Product type: Modular electromechanical safety relay
- Relay technology: Electromechanical
- Contact mechanism: Forcibly guided / mechanically linked
- Contact classification: Class A
- Contact configuration: 2 NO + 2 NC
- Number of contacts: 4
- Nominal coil voltage: 120 V AC
- Supply frequency: 50/60 Hz
- Minimum operating voltage: 93 V AC
- Nominal coil consumption: Approximately 1.1 VA
- Rated contact current: 6 A
- Rated switching voltage: 250 V AC
- Rated switching capacity (AC-1): 1,500 VA
- Contact material: Silver tin oxide (AgSnO)
- Relay operation: Monostable / non-latching
- Typical operate time: 12 ms
- Typical release time: 10 ms
- Mechanical life: 10 million operations
- Electrical life: 100,000 operations under specified test conditions
- Coil status indication: Integrated LED
- Terminal type: Screw terminals
- Mounting type: 35 mm DIN rail
- Module width: 22.5 mm
- Dimensions (W × H × D): Approximately 22.5 × 86.2 × 100.3 mm
- Ambient operating temperature: −40 to +70 °C
- Protection rating: IP20
- Contact standard: EN 61810-3
- Machinery safety reference: EN ISO 13849-1
- Functional safety reference: IEC 61508
- Country of origin: Italy
- Primary applications: Industrial machinery, monitored switching circuits and safety-related automation systems
The Finder 7S.34.8.120.4220 incorporates Class A forcibly guided contacts to support reliable fault detection in industrial control systems. Unlike conventional relay arrangements, the normally open and normally closed contacts are mechanically linked so that specified contact failures produce a detectable inconsistency in their switching positions.
If a normally open contact becomes welded closed, the mechanical guidance prevents the normally closed contacts from returning to their closed positions. An appropriately designed external monitoring circuit can detect this condition and prevent further machine operation until the fault has been addressed.
The 2 NO + 2 NC arrangement provides flexibility for applications requiring both switching and feedback. The normally open contacts can be used to switch compatible control loads, while the normally closed contacts can be incorporated into feedback monitoring circuits connected to a safety controller or other suitable diagnostic system.
This design makes the Finder 7S.34.8.120.4220 useful for machinery safety applications, including monitored output stages, machine guarding and emergency-stop control interfaces. However, the relay itself is not a complete standalone safety controller. The safety performance of an installation depends on the overall system architecture, diagnostic coverage, component reliability and validation.
120 V AC Coil Operation and Industrial Control Panel Integration
Unlike the DC-powered versions in the Finder 7S range, the 7S.34.8.120.4220 features a 120 V AC coil. This makes it suitable for industrial equipment using compatible AC control voltages, including machinery control cabinets and automation installations.
The relay's 22.5 mm-wide housing is designed for installation on a standard 35 mm DIN rail, helping conserve space in electrical control panels. Its screw terminals provide secure electrical connections and are suitable for conventional industrial wiring practices.
An integrated LED coil status indicator provides a visual indication of coil energisation, assisting with commissioning and troubleshooting. The LED indicates the electrical state of the coil rather than independently confirming the mechanical condition of every contact.
The Finder 7S.34.8.120.4220 has an IP20 protection rating and should be installed inside a suitable protective enclosure. Its operating temperature range of −40 to +70 °C supports use across a wide range of industrial environments, subject to the manufacturer's installation requirements.
Typical Applications
- Industrial machinery safety-related control circuits.
- Safety PLC switching and feedback interfaces.
- Emergency-stop control systems with appropriate external monitoring.
- Machine guarding and interlocking systems.
- Industrial automation control panels.
- Manufacturing and production line equipment.
- Conveyor and material-handling machinery.
- Packaging and processing machinery.
- Industrial lifting and handling equipment.
- Escalator and lift control systems.
- Automated warehouse equipment.
- Monitored relay output circuits.
- Applications requiring two normally open and two normally closed forcibly guided contacts.
