Finder 77.A1.9.024.8250 – 77 Series Modular solid state relays

Why Choose the Finder 77.A1.9.024.8250 Solid State Relay?

The Finder 77.A1.9.024.8250 is a high-performance single-phase solid state relay (SSR) designed for reliable, silent and contactless switching of AC electrical loads in industrial automation and control systems. As part of the Finder Series 77 solid state relay range, it provides a durable semiconductor switching solution for industrial heating, lighting, machinery and automated electrical installations.

Unlike conventional electromechanical relays, this solid state relay uses semiconductor switching technology without moving electrical contacts. Its zero-crossing switching function activates the output close to the zero-voltage point of the AC waveform, helping reduce electrical interference and switching stress when controlling suitable loads. Contactless operation also eliminates mechanical contact bounce and provides excellent endurance for applications requiring frequent switching.

With a rated output current of 25 A, a 24–280 V AC load voltage range and a 3–32 V DC control input, the Finder 77.A1.9.024.8250 is ideal for industrial control systems requiring low-voltage DC activation of AC electrical loads. Its compact hockey-puck housing, relay-style terminal arrangement and panel or heatsink mounting design enable straightforward installation within electrical control cabinets.

Key Advantages

• Reliable 25 A single-phase solid state relay for industrial AC load switching.
• 3–32 V DC control input suitable for compatible PLC outputs and electronic control circuits.
• 24–280 V AC load voltage range supports a wide variety of industrial electrical applications.
• Zero-crossing switching helps minimise electrical interference when controlling suitable AC loads.
• Contactless semiconductor operation provides silent, spark-free and bounce-free switching.
• High operational endurance without mechanical contact wear.
• Compact hockey-puck housing with a protective folding screw cover.
• Relay-style terminal arrangement simplifies separation of control and load wiring.
• Panel or heatsink mounting supports flexible integration into industrial electrical assemblies.
• IP20 protection rating for installation inside suitable electrical enclosures.

Key Features

• Finder Series 77 industrial solid state relay.
• 25 A rated output current with appropriate thermal management.
• 24–280 V AC switched load voltage.
• 3–32 V DC control voltage range.
• Single-phase, 1 normally open (SPST-NO equivalent) output.
• Zero-crossing switch-on technology.
• Contactless semiconductor switching for high operational endurance.
• Silent operation without mechanical contact bounce.
• Low-power DC control input for compatible automation systems.
• Relay-style terminals with input and output connections on opposite sides.
• Hockey-puck construction with folding screw terminal cover.
• Screw terminal connections for secure electrical wiring.
• Panel or heatsink mounting for industrial control assemblies.
• −30 to +80 °C ambient operating temperature range, subject to thermal derating.
• Suitable for industrial heaters, lighting circuits, solenoids and contactor control applications.

Reliable Contactless Switching for Industrial Automation

Solid state relays such as the Finder 77.A1.9.024.8250 use electronic semiconductor components rather than moving mechanical contacts to control electrical loads. When the specified 3–32 V DC control signal is applied, the relay activates its AC output switching circuit. Its zero-crossing switching technology delays turn-on until the AC voltage waveform approaches zero, helping reduce switching disturbances when controlling suitable resistive loads.

The Finder Series 77 is designed for industrial applications where quiet operation, high switching endurance and reliable repetitive switching are important. The 77.A1.9.024.8250 combines a 25 A output rating with a wide AC switching voltage range and low-voltage DC control, making it particularly suitable for heating equipment, industrial lighting and automated process control. Because semiconductor switching generates heat during operation, appropriate heatsink selection and thermal derating are essential. Solid state relays also exhibit off-state leakage current and do not provide mechanical isolation, so correctly rated protective and isolation devices must be installed separately.

Typical Applications

• Industrial electric heating and temperature control systems.
• Resistive heater banks and heating element switching.
• Industrial ovens, furnaces and process heating equipment.
• Packaging and automated manufacturing machinery.
• Industrial lighting and compatible lamp switching circuits.
• Solenoid and contactor control applications.
• PLC-controlled electrical switching and automation systems.
• Electrical control cabinets and industrial switching assemblies.
• OEM machinery requiring silent and repetitive AC load switching.
• Industrial process control and automated electrical installations.