Finder 77.B1.8.230.8250 – 77 Series Modular solid state relays

Why Choose the Finder 77.B1.8.230.8250 Solid State Relay?

The Finder 77.B1.8.230.8250 is a high-current 40 A AC-output solid state relay (SSR) designed for silent, contactless switching in industrial automation, electric heating, lighting control and machinery applications. Part of the Finder Series 77 solid state relay range, this model features a robust hockey puck-style housing, zero-crossing switching technology and a panel-mounting arrangement suitable for installation on a compatible heat sink or electrical cabinet mounting surface.

Featuring a 24–280 V AC output switching range and a 230 V AC nominal control input, the Finder 77.B1.8.230.8250 provides a rated output current of 40 A, subject to appropriate thermal management and operating conditions. Its control input accepts 90–280 V AC, allowing integration into compatible mains-voltage control systems.

The relay incorporates one normally open electronic output (1 NO / SPST-NO) and uses zero-crossing turn-on technology to reduce switching disturbances in suitable AC load applications. Its compact 45 × 59 × 29.4 mm enclosure, screw terminals and protective terminal covers support professional installation in industrial electrical assemblies.

Key Advantages

• 40 A rated output current for appropriately designed industrial AC switching applications.
• 24–280 V AC output switching range for compatible single-phase electrical loads.
• 90–280 V AC control input with a nominal control voltage of 230 V AC.
• Zero-crossing switching helps reduce electrical disturbances when switching suitable AC loads.
• Contactless semiconductor operation eliminates mechanical contact wear and bounce.
• Silent switching for installations where acoustic noise is undesirable.
• High switching endurance for applications requiring frequent electrical switching.
• Hockey puck-style housing for panel or heat sink mounting.
• 500 A peak surge current capability for 10 ms under specified conditions.
• 4 kV input-to-output dielectric withstand for electrical separation between control and load circuits.
• LED indication for convenient monitoring of the relay input state.
• IP20 protection rating for installation within suitable electrical enclosures.

Key Features

• Finder Series 77 industrial solid state relay.
• Type 77.B1 hockey puck configuration.
• Single-phase AC load switching.
• One normally open electronic output (SPST-NO).
• 40 A rated output current.
• 24–280 V AC load switching voltage.
• 230 V AC nominal control voltage.
• 90–280 V AC operating control voltage range.
• Zero-crossing switch-on characteristic.
• Semiconductor-based contactless switching.
• Silent operation without mechanical contact movement.
• 500 A peak surge current for 10 ms.
• 600 V repetitive peak OFF-state blocking voltage.
• Low OFF-state leakage current.
• LED input status indication.
• Electrical isolation between input and output circuits.
• Screw-type electrical terminals.
• Folding protective screw covers.
• Panel or heat sink mounting.
• Suitable for resistive heating and compatible industrial AC loads.

Reliable Zero-Crossing Switching for Industrial AC Loads

The Finder 77.B1.8.230.8250 uses electronic semiconductor switching to control AC electrical loads without mechanical contacts. When the specified control voltage is applied, the relay activates its output electronically, providing silent switching and eliminating the contact bounce associated with conventional electromechanical relays.

Its zero-crossing turn-on function initiates conduction close to the point where the AC voltage waveform crosses zero. This characteristic can help reduce switching transients and electromagnetic interference in compatible resistive loads, particularly electrical heating applications.

The relay is rated for 40 A output current, making it suitable for higher-current AC load control when installed with the necessary thermal management. Its specified 500 A peak surge current capability for 10 ms supports short-duration current surges within the manufacturer's limits.

Unlike a slim DIN rail solid state relay, the Finder 77.B1.8.230.8250 features a hockey puck-style housing intended for mounting on a suitable panel surface or heat sink. This construction supports thermal coupling to an appropriately selected heat sink where required.

Thermal management is essential. The relay can dissipate approximately 48 W at its rated output current. The mounting surface, heat sink thermal resistance, ventilation and ambient temperature must therefore be considered to prevent overheating and ensure the relay operates within its specified limits.

The relay provides 4 kV AC input-to-output dielectric withstand, supporting separation between the control and load circuits. Its LED indication allows the control input condition to be checked during commissioning and maintenance.

As with other solid state relays, the output can exhibit a small leakage current when switched off. The Finder 77.B1.8.230.8250 therefore must not be treated as an electrical isolator. Appropriate protective devices and a separate means of isolation should be incorporated where required.

Typical Applications

• Industrial electric heating control.
• Resistive heating element switching.
• Industrial ovens and heating equipment.
• Temperature-controlled manufacturing processes.
• Commercial and industrial lighting systems.
• AC solenoid and contactor driver circuits.
• Industrial machinery and manufacturing equipment.
• Programmable logic controller (PLC) controlled switching.
• Building automation and electrical control systems.
• Industrial process control panels.
• High-frequency switching applications.
• Equipment requiring silent electrical switching.
• OEM industrial control and automation assemblies.