Finder 77.G1.8.230.8250 – 77 Series Modular solid state relays

Why Choose the Finder 77.G1.8.230.8250 100 A Solid State Relay?

The Finder 77.G1.8.230.8250 is a high-current single-phase solid state relay (SSR) designed for reliable, silent and contactless switching of industrial AC electrical loads. Part of the Finder 77 Series, this industrial switching device combines a substantial 100 A rated load current with electronic semiconductor technology, making it particularly suitable for demanding heating, temperature control and industrial automation applications.

Featuring a 90–280 V AC control input, a 24–280 V AC load switching range and zero-crossing switching, the Finder 77.G1.8.230.8250 provides an effective solution for controlling high-current AC loads using a compatible mains-voltage control signal. Unlike DC-input solid state relays, this version can be operated directly from a suitable AC control circuit without requiring a separate low-voltage DC control supply.

The relay features a compact hockey puck-style housing, one normally open equivalent output, screw terminal connections and a folding protective terminal cover. Its relay-style terminal arrangement places the control and load connections on opposite sides of the housing for practical industrial wiring.

Designed for installation on a suitable metal panel or heatsink, the Finder 77.G1.8.230.8250 offers high switching endurance, quiet operation and dependable performance in correctly designed industrial electrical installations.

Key Advantages

• 100 A rated load current supports demanding industrial AC switching applications when correctly heatsinked.
• 90–280 V AC control voltage allows operation from compatible AC control circuits.
• 24–280 V AC load voltage range accommodates common industrial and commercial AC loads.
• Zero-crossing switching helps reduce electrical interference when switching suitable resistive loads.
• Silent semiconductor operation eliminates the mechanical clicking associated with electromechanical relays.
• Contactless switching avoids mechanical contact bounce and mechanical contact wear.
• High switching endurance is ideal for applications involving frequent switching cycles.
• Fast electronic operation supports automated temperature and process control.
• Single-phase 1 NO equivalent output provides a straightforward switching arrangement.
• Hockey puck-style housing provides a compact industrial mounting format.
• Folding screw terminal cover offers additional protection around the connections.
• Panel or heatsink mounting supports application-specific thermal management.
• 47–400 Hz operating frequency supports compatible AC supply systems.
• Suitable for industrial heaters, lamps, compatible solenoids and contactor-driving circuits.

Key Features

• Finder 77 Series industrial solid state relay.
• Single-phase AC output switching.
• 100 A rated load current.
• 24–280 V AC operating load voltage.
• 90–280 V AC control input.
• 230 V AC nominal control voltage.
• Zero-crossing turn-on for suitable AC loads.
• 1 NO equivalent output configuration (SPST-NO).
• 1,500 A maximum peak current for 10 ms, subject to specified conditions.
• 47–400 Hz operating frequency range.
• 0.1 mA listed off-state leakage current.
• Semiconductor switching without moving mechanical contacts.
• Silent operation without mechanical contact bounce.
• High switching endurance for frequent operating cycles.
• Compact hockey puck-style industrial housing.
• Relay-style input and output terminal arrangement.
• Screw terminal connections with folding protective cover.
• Suitable for mounting on a metal control cabinet panel or heatsink.
• IP20 protection rating.
• −30 to +80 °C ambient operating temperature range, subject to thermal derating.
• RoHS-compliant construction.

High-Current Solid State Switching for Industrial Control

The Finder 77.G1.8.230.8250 uses semiconductor components to switch AC electrical loads without the moving contacts found in conventional electromechanical relays. When a suitable AC control voltage is applied, the internal electronic switching circuit activates the output and allows current to flow through the connected load.

Because the relay has no moving output contacts, it operates silently and avoids mechanical contact bounce. This makes it especially useful for applications involving frequent switching, including industrial heating systems where a temperature controller repeatedly energises and de-energises heating elements to maintain a set temperature.

The 100 A load rating makes this model suitable for high-current applications, provided that the actual operating current remains within the manufacturer's thermal derating limits. The appropriate heatsink, electrical protection and installation conditions must be considered before operating at high loads.

Its 90–280 V AC control input is an important distinguishing feature. This enables the relay to be controlled using compatible AC-voltage signals rather than the low-voltage DC signals required by many other solid state relay models.

How Zero-Crossing Switching Works

The Finder 77.G1.8.230.8250 uses zero-crossing switching, which means the semiconductor output turns on close to the point where the AC voltage waveform crosses zero.

This switching method helps reduce electrical disturbances associated with energising suitable AC loads. It is particularly useful for resistive heating elements, where zero-crossing operation can help minimise switching-related electromagnetic interference.

Zero-crossing switching differs from random turn-on operation, where a semiconductor relay can activate at another point in the AC waveform. The correct switching method depends on the load characteristics and control requirements.

The Finder 77.G1.8.230.8250 is intended for AC load switching only. It should not be used to switch DC loads.

Thermal Management and Installation Considerations

High-current solid state relays generate heat when their semiconductor outputs conduct electricity. Correct thermal management is therefore essential for reliable operation of the Finder 77.G1.8.230.8250.

The relay is designed for mounting on a suitable metal panel or heatsink. The required heatsink performance depends on load current, ambient temperature, mounting conditions and enclosure ventilation.

The 100 A rating represents the relay's rated load capability under appropriate conditions and must not be interpreted as an unconditional continuous-current rating for every installation. The manufacturer's current-versus-temperature derating information should be used when selecting the heatsink and determining the permissible operating current.

Suitable semiconductor protection, overcurrent protection, correctly rated conductors and a means of electrical isolation should be included in the installation.

Like other solid state relays, this device can allow a small leakage current to pass when its output is switched off. It must therefore not be relied upon as a mechanical isolating device. A suitable disconnecting device should be provided wherever safe electrical isolation is required.

Typical Applications

• Industrial electric heater control.
• High-current resistive heating systems.
• Industrial ovens, furnaces and drying equipment.
• Temperature regulation and process heating installations.
• Plastic processing and manufacturing machinery.
• Packaging and production equipment.
• Industrial automation systems requiring frequent AC switching.
• Commercial and industrial heating equipment.
• Suitable high-current lighting applications.
• Compatible AC solenoid and contactor-driving circuits.
• OEM machinery and industrial electrical control panels.
• Automated equipment using compatible AC control signals.
• Applications requiring silent, contactless switching of AC loads.