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Finder 77.A1.8.230.8250 – 77 Series Modular solid state relays
Finder 77.A1.8.230.8250 is a 25 A single-phase hockey-puck solid state relay with a 90–280 V AC control input, 24–280 V AC load switching range, zero-crossing operation, screw terminals and panel or heat-sink mounting for industrial AC load control.
£25.68
Why Choose the Finder 77.A1.8.230.8250 Solid State Relay?
The Finder 77.A1.8.230.8250 is a 25 A single-phase solid state relay (SSR) from the Finder 77 Series, designed for reliable, contactless switching of AC electrical loads. Featuring a compact hockey-puck-style housing, it provides an effective switching solution for industrial heating equipment, lighting circuits, automation systems and electrical control panels.
With a 230 V AC nominal control input, an operating input range of 90–280 V AC and an output switching range of 24–280 V AC, this relay allows an AC control signal to operate a separate AC load circuit. Its 25 A rated output current and single normally open semiconductor output make it suitable for appropriately rated industrial applications.
The Finder 77.A1.8.230.8250 incorporates zero-crossing switching, which initiates conduction near the AC voltage zero crossing to help reduce switching interference. Its silent operation, screw terminals, protective terminal cover and panel or heat-sink mounting arrangement make it particularly suitable for installations requiring frequent switching without mechanical contact wear.
Key Advantages
- 25 A rated output current for appropriately rated single-phase AC loads.
- 230 V AC nominal control input for industrial AC control systems.
- 90–280 V AC input operating range for flexible control integration.
- 24–280 V AC load switching range for compatible electrical equipment.
- Zero-crossing turn-on helps minimise switching interference.
- Contactless semiconductor switching eliminates mechanical contact bounce.
- Silent operation for equipment requiring frequent switching.
- Single normally open output for straightforward load control.
- Hockey-puck-style housing for direct panel or heat-sink mounting.
- Relay-style terminal arrangement with input and output connections on opposite sides.
- Screw terminals and protective cover for practical installation.
- IP20 protection rating for use within suitable electrical enclosures.
Key Features
- Finder 77 Series industrial solid state relay.
- Model: 77.A1.8.230.8250.
- Single-phase AC output.
- Output configuration: 1 NO / SPST-NO equivalent.
- Rated output current: 25 A.
- Rated output voltage: 230 V AC.
- Load switching voltage: 24–280 V AC.
- Nominal control voltage: 230 V AC.
- Control input operating range: 90–280 V AC.
- Control input frequency: 50/60 Hz.
- Switching function: Zero-crossing turn-on.
- Contactless electronic switching.
- Relay-style terminals positioned on opposite sides.
- Hockey-puck housing with protective screw cover.
- Panel or heat-sink mounting.
- Screw terminal connections.
- Ambient operating temperature: −30 to +80 °C.
- Protection rating: IP20.
Reliable Zero-Crossing Switching for Industrial AC Loads
The Finder 77.A1.8.230.8250 uses an electronic semiconductor output instead of mechanical relay contacts. When an appropriate AC control voltage is applied to its input terminals, the relay activates its output at a suitable AC voltage zero crossing, allowing current to flow through the connected load. When the control input is removed, the output stops conducting according to the semiconductor switching characteristic.
This zero-crossing switching method is particularly useful for suitable resistive loads, including industrial heating equipment, where reduced switching interference and frequent operation are desirable. The relay should be mounted on an appropriately selected heat sink or thermally suitable panel arrangement, with load current, ambient temperature, protective devices and heat dissipation considered during installation. As a semiconductor switching device, it does not replace a mechanical isolator.
Typical Applications
- Industrial electrical heating and temperature control.
- Heating elements and resistive load switching.
- Industrial lighting control systems.
- Solenoid and contactor control circuits.
- Industrial automation and electronic load control.
- Machinery requiring frequent, silent AC switching.
- Process control and manufacturing equipment.
- Packaging and production machinery.
- OEM electrical control assemblies.
- Panel-mounted semiconductor switching installations.
Technical Specifications
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| Device Type | Solid State Relay | |
|---|---|---|
| Terminal Type | Screw | |
| Mounting Type | Panel | |
| Load Voltage | 24–280 V AC | |
| Manufacturer | Finder | |
| Series | 77 Series | |
| Manufacturer part number | 77.A1.8.230.8250 | |
| Product type | Solid state relay | |
| Housing style | Hockey puck | |
| Number of phases | 1 | |
| Output contact equivalent | 1 normally open (SPST-NO) | |
| Rated output current | 25 A | |
| Rated output voltage | 230 V AC | |
| Load voltage range | 24–280 V AC | |
| Nominal control voltage | 230 V AC | |
| Control voltage range | 90–280 V AC | |
| Control supply type | AC, 50/60 Hz | |
| Switching mode | Zero-crossing | |
| Terminal arrangement | Relay style, input and output on opposite sides | |
| Connection type | Screw terminals | |
| Mounting method | Panel or heat-sink mounting | |
| Housing width | 45 mm | |
| Housing height | 59 mm | |
| Housing depth | 29.4 mm | |
| Ambient operating temperature | −30 to +80 °C | |
| Protection classification | IP20 | |
| Product category | Solid State Relays |
Frequently Asked Questions
What is the Finder 77.A1.8.230.8250 used for?
The Finder 77.A1.8.230.8250 is a 25 A single-phase solid state relay used for contactless switching of suitable AC loads, including heating equipment, lighting and industrial control circuits.
What control voltage does the Finder 77.A1.8.230.8250 require?
The relay has a 230 V AC nominal control input and operates within a specified input range of 90–280 V AC at 50/60 Hz.
What is the maximum rated output current?
The Finder 77.A1.8.230.8250 has a 25 A rated output current. The permissible operating current depends on the load, heat-sink selection and thermal conditions.
What AC load voltage can this solid state relay switch?
The relay is designed for an AC load switching range of 24–280 V AC, with a nominal output voltage of 230 V AC.
What does zero-crossing switching mean?
Zero-crossing switching means the relay initiates output conduction near the point where the AC voltage crosses zero. This helps reduce electrical switching interference in suitable applications.
Does the Finder 77.A1.8.230.8250 contain mechanical switching contacts?
No. It uses a semiconductor switching output rather than mechanical contacts, enabling silent operation without mechanical contact bounce.
Can the Finder 77.A1.8.230.8250 be mounted directly on a panel?
Yes. Its hockey-puck-style housing is designed for mounting on a suitable control cabinet panel or heat sink. Adequate heat dissipation must be provided for the operating load.
Does this relay include an integrated DIN-rail heat sink?
No. The Finder 77.A1.8.230.8250 is a panel or heat-sink-mounted hockey-puck relay, rather than the modular DIN-rail version with an integrated heat sink.
Can the Finder 77.A1.8.230.8250 switch DC loads?
No. This model is intended for AC load switching. Its AC semiconductor output should not be used as a general-purpose DC load switch.
What is the difference between the Finder 77.A1.8.230.8250 and 77.21.9.024.8251?
The 77.A1.8.230.8250 is a panel-mounted hockey-puck relay with a 90–280 V AC control input and zero-crossing switching. The 77.21.9.024.8251 is a modular DIN-rail relay with a DC control input and random turn-on switching.
Does this solid state relay provide safe electrical isolation when switched off?
No. A solid state relay can exhibit leakage current when switched off and does not provide the same load isolation as a mechanical isolating switch. Suitable electrical isolation and circuit protection must be provided separately.
Trusted by Industrial Automation and Electrical Engineering Professionals
Finder 77 Series solid state relays are designed for electrical engineers, industrial automation specialists, machinery manufacturers and panel builders requiring silent, contactless AC switching, reliable electronic control and flexible installation within industrial electrical systems.
