Finder 55.34.9.072.0000T – 55 Series Miniature General Purpose Relays – Railway

Why Choose the Finder 55.34.9.072.0000T 72 V DC Industrial Plug-In Relay?

The Finder 55.34.9.072.0000T is a high-quality 7 A, four-pole industrial electromechanical relay designed for reliable switching in automation systems, railway-related control equipment, electrical panels and industrial machinery. Part of the established Finder 55 Series, this miniature plug-in relay combines a 72 V DC coil, four independent changeover contacts and robust electrical switching characteristics in a compact, serviceable component.

Featuring a 4PDT (four-pole double-throw / 4 CO) contact arrangement, the Finder 55.34.9.072.0000T allows four separate electrical circuits to be controlled using a single coil supply. Each changeover contact provides common, normally open and normally closed connections, making the relay suitable for auxiliary switching, control logic, equipment monitoring and multi-circuit signalling.

The T-suffix version belongs to Finder's relay range for railway-related applications, where dependable operation and compatibility with suitable DC control systems are important. With silver nickel (AgNi) contacts, a 7 A rated contact current, a 250 V AC maximum switching voltage and convenient plug-in socket mounting, this relay provides a practical solution for engineers, maintenance technicians and industrial equipment manufacturers.

Key Advantages

• 72 V DC nominal coil: Designed for compatible industrial and railway-related DC control supplies.
• Four changeover contacts: Switches four separate circuits using a single control signal.
• 7 A rated contact current: Suitable for appropriately rated industrial control loads.
• 250 V AC maximum switching voltage: Supports a broad range of electrical control applications.
• Silver nickel contacts: Provides dependable general-purpose switching characteristics.
• Plug-in mounting: Allows straightforward installation and replacement with a compatible relay socket.
• Compact four-pole design: Reduces the number of separate relays required for multi-circuit switching.
• Low coil current: Approximately 15 mA nominal coil current.
• Fast switching response: Approximately 11 ms operate time and 3 ms release time.
• Monostable operation: Contacts return to their normal positions when the coil is de-energised.
• Industrial temperature capability: Suitable for specified operating temperatures from −40 to +85 °C.
• Serviceable construction: Socket mounting helps simplify routine maintenance and relay replacement.
• Finder 55 Series platform: Designed for industrial control and automation applications.

Key Features

• Finder 55 Series miniature electromechanical relay.
• Type 55.34 four-pole plug-in relay.
• 72 V DC nominal coil voltage.
• 4PDT / 4 CO / 4 Form C contact configuration.
• Four independent changeover contact sets.
• 7 A rated contact current.
• 250 V AC maximum switching voltage.
• 1,750 VA maximum rated switching load under specified resistive conditions.
• Silver nickel (AgNi) contact material.
• 4 kΩ nominal coil resistance.
• 15 mA nominal coil current.
• Approximately 1.08 W nominal coil consumption.
• 50.4 V DC must-operate voltage.
• 7.2 V DC must-release voltage.
• 11 ms typical operate time.
• 3 ms typical release time.
• Non-latching electromechanical operation.
• Plug-in socket mounting.
• 14-pin electrical connection arrangement.
• −40 to +85 °C operating temperature range.
• Compact miniature relay housing.
• T-suffix version for railway-related applications.

Four-Pole Changeover Switching for Industrial Control

The Finder 55.34.9.072.0000T provides four independent changeover contact sets operated by a single 72 V DC electromagnetic coil. This configuration is especially useful where several control or signalling circuits must change state together.

Each contact set contains a common terminal, a normally closed terminal and a normally open terminal. When the coil is energised, the common contact transfers from the normally closed connection to the normally open connection. Removing the coil supply allows the contacts to return to their normal positions.

In practical control applications, one contact may be assigned to auxiliary switching, another to equipment status indication and the remaining contacts to additional signalling or interlocking functions. This allows engineers to simplify control circuitry while retaining separate switching paths.

All four contact sets must be operated within their specified electrical ratings. The 7 A contact rating applies under defined conditions and should not be assumed to apply equally to every inductive, capacitive or DC load.

Reliable 72 V DC Coil Operation

The 72 V DC coil makes this relay suitable for systems designed around a corresponding DC control supply. Its nominal resistance of 4 kΩ and nominal current of 15 mA result in approximately 1.08 W of coil consumption at the rated voltage.

The relay has a specified must-operate voltage of 50.4 V DC and a must-release voltage of 7.2 V DC. These values describe particular switching thresholds and should not be interpreted as the complete permitted continuous operating voltage range. Engineers should consult Finder's applicable coil operating curves when assessing supply variation and ambient temperature.

With a typical 11 ms operate time and 3 ms release time, the Finder 55.34.9.072.0000T supports responsive electromechanical switching in suitably designed industrial control systems.

Appropriate coil suppression should be considered where the relay is controlled by electronic outputs. Suppression components may affect release timing and should be selected according to the requirements of the complete circuit.

T-Suffix Relay Version for Railway-Related Equipment

The T suffix identifies a Finder 55 Series version associated with railway applications. Such applications can involve specialised requirements relating to control supply variation, vibration, mechanical shock and environmental operating conditions.

The Finder 55.34.9.072.0000T can be considered for suitable auxiliary control and signalling functions in railway-related equipment, provided the complete design satisfies the relevant application requirements.

Engineers should verify the manufacturer's current technical documentation and the approvals applicable to the exact relay version before specifying it for a regulated railway installation. Selection of a railway-related relay variant does not, by itself, establish compliance of the finished equipment with every applicable railway standard.

Convenient Plug-In Socket Mounting

The Finder 55.34.9.072.0000T is designed for plug-in socket mounting, making it particularly practical for electrical control panels and serviceable industrial equipment.

When installed in a compatible relay socket, the component can be removed and replaced without directly unsoldering electrical connections. This can help reduce maintenance time and simplify the replacement of compatible relays in existing control assemblies.

The relay uses a 14-pin connection arrangement and can be paired with a suitably selected Finder socket. Socket compatibility must be confirmed using the manufacturer's technical documentation, including terminal layout, voltage rating, contact rating and mounting requirements.

For DIN rail installation, an appropriate socket or interface assembly is required. The relay itself is a plug-in component rather than a complete DIN rail-mounted relay module.

Typical Applications

• Industrial automation and machine control systems.
• Railway-related auxiliary control equipment.
• Electrical control panels and switchgear assemblies.
• 72 V DC industrial control circuits.
• Multi-circuit switching and changeover functions.
• Equipment status indication and auxiliary signalling.
• Industrial electrical interlocking circuits.
• PLC-controlled switching interfaces with compatible outputs.
• Process monitoring and control equipment.
• Transport infrastructure control equipment.
• Building management and automation systems.
• Heating, ventilation and air conditioning control circuits.
• Motor starter auxiliary control applications.
• OEM industrial electrical equipment.
• Maintenance and replacement of compatible Finder 55.34 relays.