Finder 77.D3.8.230.8671 – 77 Series Modular solid state relays

Why Choose the Finder 77.D3.8.230.8671 Three-Phase Solid State Relay?

The Finder 77.D3.8.230.8671 is a 60 A three-phase solid state relay (SSR) designed for contactless switching of AC electrical loads in industrial heating, process control and automation applications. Part of the Finder Series 77, this relay combines three semiconductor switching outputs with a compact hockey puck-style housing for installation onto a suitable mounting surface or heatsink.

Featuring a 90–280 V AC control input and a 24–660 V AC load switching range, the Finder 77.D3.8.230.8671 provides an interface between AC control circuits and three-phase electrical loads. Its three normally open outputs (3 NO / 3PST-NO) support a rated load current of up to 60 A, subject to appropriate thermal management, load characteristics and the manufacturer's operating limits.

The relay features random turn-on switching, allowing its semiconductor outputs to respond to the applied control signal without waiting for an AC voltage zero crossing. Its contactless design provides silent, bounce-free switching, making it a practical choice for industrial applications requiring repeated electrical load control.

Key Advantages

• Three-phase switching capability with three normally open semiconductor outputs.
• 60 A load current rating for appropriately rated industrial AC loads.
• 24–660 V AC load voltage range for a variety of industrial electrical systems.
• 90–280 V AC control voltage range for compatible AC control circuits.
• Random turn-on switching for applications requiring switching without zero-cross synchronisation.
• Contactless semiconductor technology eliminates mechanical contact wear.
• Silent switching operation without mechanical contact noise.
• Spark-free and bounce-free switching during normal operation.
• Hockey puck-style housing for panel or heatsink mounting.
• Contactor-style terminal arrangement with input and output terminals on adjacent sides.
• Screw terminal connections for industrial electrical wiring.
• Suitable for repeated switching operations in automation and process control systems.

Key Features

• Finder Series 77 solid state relay.
• Type 77.D3 three-phase switching configuration.
• Maximum load current: 60 A.
• Control input voltage: 90–280 V AC.
• Nominal control voltage: 230 V AC.
• Switched load voltage: 24–660 V AC.
• Output configuration: 3 NO (3PST-NO).
• Number of switched phases: 3.
• Switching method: Random turn-on.
• Semiconductor switching technology for contactless operation.
• Hockey puck-style construction for industrial mounting.
• Panel or heatsink mounting for integration into electrical assemblies.
• Contactor-style terminal layout.
• Screw terminal electrical connections.
• Operating frequency: 47–400 Hz.
• Operating ambient temperature: −30 °C to +80 °C.
• RoHS-compliant construction.

Reliable Three-Phase Switching for Industrial Heating and Automation

The Finder 77.D3.8.230.8671 enables three-phase AC loads to be controlled electronically using a compatible AC control signal. Its 90–280 V AC input range makes it suitable for integration into appropriately designed industrial control circuits, including temperature controllers, automation equipment and machinery control systems.

Unlike zero-cross solid state relays, the Finder 77.D3.8.230.8671 uses random turn-on switching. This means the semiconductor outputs can begin conducting in response to the control signal without waiting for the AC waveform to pass through zero. The switching characteristic should be selected according to the electrical behaviour and requirements of the connected load.

For applications approaching its 60 A load rating, appropriate heatsinking and thermal design are essential. The allowable operating current depends on ambient temperature, mounting conditions and load characteristics. Suitable upstream protection, conductor sizing and manufacturer-specified derating must be considered. As solid state relays can exhibit off-state leakage current, a separate isolating device is required wherever safe electrical isolation is necessary.

Typical Applications

• Three-phase industrial electric heating systems.
• Industrial ovens and process heating equipment.
• Three-phase resistance heater banks.
• Temperature-controlled manufacturing processes.
• Industrial machinery and automation control panels.
• AC-controlled semiconductor switching systems.
• Packaging and production line equipment.
• Industrial process control installations.
• Repeated switching of compatible three-phase AC loads.
• OEM machinery and electrical panel manufacturing.
• Applications requiring silent, contactless switching.
• Industrial control systems requiring random turn-on operation.