Three-Phase Solid State Relay (SSR) 25A: Silent, High-Performance Control

Upgrade Your Industrial Control: Speed, Silence & Reliability

Traditional mechanical relays and contactors have moving parts that wear out, create noise, and limit switching speed. In modern industrial control, you need a smarter, more efficient solution that delivers precise, long-lasting performance without compromise.

Our Three-Phase Solid State Relay (SSR) is a cutting-edge industrial control appliance designed for high-powered, intelligent, and silent operation. Rated for 25 Amps and capable of handling 24-480VAC output, this SSR is perfect for demanding three-phase applications. It offers flexible control with a wide input voltage range of 4-32VDC or 80-250VAC, making it compatible with various control systems.

Unlike conventional relays, this SSR has no moving parts, eliminating wear-and-tear, contact bounce, and electrical noise. It switches ON and OFF much faster, features zero-voltage turn-on and zero-current turn-off for minimal interference, and operates reliably in temperatures from -40°C to 100°C. An integrated LED indicator provides instant visual confirmation of its "ON" or "OFF" status. Experience superior performance, enhanced efficiency, and a truly green-friendly control solution.

Key Features & Benefits

• High-Power 25A Capacity: Capable of switching significant loads for robust performance in industrial applications.
• Wide Output Voltage Range (24-480VAC): Highly versatile, suitable for a broad spectrum of three-phase AC systems.
• Flexible Control Input: Accepts both 4-32VDC (for PLC/microcontroller control) and 80-250VAC signals, ensuring broad compatibility.
• Silent Operation: No moving parts mean no audible clicking, ideal for noise-sensitive environments.
• Extended Lifespan: Without mechanical wear, SSRs offer significantly longer operational lives compared to electromechanical relays, reducing maintenance.
• Fast Switching & Zero-Cross Technology: Switches ON/OFF much faster and incorporates zero-voltage turn-on and zero-current turn-off, minimising electrical noise and extending load life.
• LED Status Indicator: A clear LED light provides immediate visual feedback on the relay's "ON" or "OFF" status.
• Wide Operating Temperature: Functions reliably across a broad range from -40°C to 100°C, suitable for diverse industrial conditions.
• Enhanced Safety: Protect Panel design and adherence to IEC standards ensure reliable and safe operation.
• Green & Efficient: Contributes to a more energy-efficient and environmentally friendly control system.

Understanding Solid State Relays (SSRs)

A Solid State Relay (SSR) is an electronic switching device that, unlike an electromechanical relay, has no moving parts. It uses semiconductor components (like TRIACs or MOSFETs) to switch electrical power.

How it works:

The core of an SSR is often an optoisolator (or optocoupler). This component internally separates the input control circuit from the output load circuit using light (an infrared LED and a photosensitive device). When a control signal is applied to the input, the LED illuminates, triggering the photosensitive device on the output side, which then activates the switching semiconductors. This optical isolation provides excellent electrical separation between low-voltage control signals and high-voltage loads, enhancing safety and preventing interference.

The output circuit of most standard SSRs behaves like a Normally-Open, Single-Pole, Single-Throw (SPST-NO) switch, providing simple ON/OFF control. SSRs are highly favoured for their speed, silent operation, and long lifespan in comparison to traditional relays.

Important: Heat Dissipation

Solid State Relays generate heat during operation, proportional to the current being switched. Proper heat dissipation is critical for the SSR's performance and lifespan. To ensure optimal operation and prevent overheating, this unit MUST be used with a suitable heatsink base or a finned heatsink. Refer to the provided heat dissipative power curve (if displayed) for specific requirements based on your current load.

Technical Specifications

• Product Type: Three-Phase Solid State Relay (SSR)
• Rated Current: 25 Amps (A)
• Output Current Range: 0.5A ~ 25A (For optimal heatsink sizing)
• Operation Voltage (Output): 24V ~ 480V AC
• Control Voltage (Input):
• 4-32V DC
• 80-250V AC
• Operating Temperature Range: -40°C to 100°C
• Indicator: LED (showing "ON" or "OFF" status)
• Protection: Protect Panel design
• Standards: IEC Standard Compliant
• Switching Type: Zero-Cross Turn-On / Zero-Current Turn-Off
• Isolation: Optoisolated Input/Output
• Dimensions: [Add typical dimensions if available, e.g., 58mm x 45mm x 32mm]
• Mounting: Panel Mount (requires heatsink)

Ideal Applications

This 25A Three-Phase Solid State Relay is an excellent choice for precise and reliable control in a wide range of demanding industrial and commercial applications, including:

• Heating Elements: Ovens, furnaces, plastic moulding machines, heating baths.
• Motor Control: AC motors, pumps, fans (e.g., for soft start or frequent switching).
• Lighting Control: High-power industrial lighting systems.
• Power Supplies: Regulated power supplies and power factor correction.
• Packaging Machinery: Precise control of heating and motion.
• HVAC Systems: Controlling compressors, heaters, and fans.
• Industrial Automation: General-purpose high-current switching.

Important Installation & Safety Notice

Installation, wiring, and maintenance of this Solid State Relay must ONLY be performed by a qualified electrician or trained technical personnel in strict accordance with all local electrical codes, safety regulations, and the manufacturer's instructions. Always ensure the main power supply to the circuit is disconnected and locked out before any work is carried out. Improper installation, inadequate heatsinking, or exceeding specified current/voltage ratings can lead to overheating, equipment damage, electrical shock, or fire. Always use an appropriately sized heatsink for the expected current load.

Customer Reviews

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"Great for Precise Motor Control"

"Using this 25A SSR for a three-phase motor in our packaging machine. The fast switching and silent operation are exactly what we needed for our precision processes. The flexible input voltage meant it integrated seamlessly with our existing PLC." — Automation Technician, Birmingham,

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"High Quality, Excellent Value"

"For the price, this SSR offers fantastic quality. It's robust, handles our load perfectly, and the wide operating temperature range gives us confidence. Just make sure you pair it with a good heatsink, which is standard for these devices." — Electrical Contractor, Manchester

Frequently Asked Questions (FAQs)

Q1: Do I need a heatsink for this Solid State Relay?

A1: Yes, absolutely. This SSR will generate heat during operation. An appropriately sized heatsink (either a heatsink base or a finned heatsink) is crucial to dissipate this heat and ensure the SSR operates within its safe temperature limits, preventing damage and extending its lifespan.

Q2: What's the difference between DC control and AC control?

A2: DC control (4-32VDC) means the relay is switched ON/OFF by a low-voltage direct current signal, typically from a PLC, microcontroller, or push-button. AC control (80-250VAC) means the relay is switched by a standard alternating current line voltage, common in many industrial control circuits. You must choose the correct input type for your control system.

Q3: Can this SSR be used for single-phase applications?

A3: While designed for three-phase use, a three-phase SSR could technically be wired for single-phase, but it would be over-specified and likely not cost-effective. We recommend selecting a dedicated single-phase SSR for single-phase applications.

Q4: What does "zero-voltage turn-on" and "zero-current turn-off" mean?

A4: This advanced feature ensures the SSR turns on only when the AC output voltage crosses zero volts and turns off when the AC current crosses zero amps. This significantly reduces electrical noise, voltage spikes, and electromagnetic interference (EMI), protecting both the SSR and your connected load.

Q5: What types of loads is this 25A SSR suitable for?

A5: This 25A SSR is ideal for resistive loads (like heating elements), and also suitable for many inductive loads (like motors, transformers) due to its zero-crossing feature, provided the inrush current of inductive loads does not exceed the SSR's surge current rating. Always ensure your load current is within the SSR's specifications and consider a safety margin.

Experience superior, silent control for your three-phase power applications. Order your 25A Three-Phase Solid State Relay today!