Three-Phase Solid State Relay (SSR) 40A: High-Power, Silent, & Ultra-Reliable Control

Command High-Current Applications with Unmatched Precision & Durability

In demanding industrial environments, managing high-powered three-phase equipment requires a robust, high-performance control solution. Traditional mechanical relays and contactors, with their inherent moving parts, suffer from wear and tear, generate noise, and have limited switching speeds. For modern automation, you need an intelligent, silent, and incredibly reliable alternative.

Our Three-Phase Solid State Relay (SSR) is a cutting-edge industrial control appliance engineered for heavy-duty, intelligent, and silent operation. Rated for a substantial 40 Amps and capable of handling 24-480VAC output, this SSR is perfect for the most demanding three-phase applications. It offers flexible control with a wide input voltage range of 4-32VDC or 80-250VAC, ensuring seamless compatibility with various control systems, from PLCs to manual switches.

Unlike conventional relays, this 40A SSR boasts no moving parts, effectively eliminating wear-and-tear, contact bounce, and disruptive electrical noise. It switches ON and OFF significantly faster, features zero-voltage turn-on and zero-current turn-off for minimal interference, and operates reliably across a wide temperature spectrum from -40°C to 100°C. An integrated LED indicator provides instant visual confirmation of its "ON" or "OFF" status. Experience superior performance, enhanced energy efficiency, and a truly robust, environmentally friendly control solution.

Key Features & Benefits

• High-Power 40A Capacity: Capable of switching substantial loads for robust and stable performance in demanding industrial applications.

• Wide Output Voltage Range (24-480VAC): Highly versatile, suitable for a broad spectrum of three-phase AC power systems.

• Flexible Control Input: Accepts both 4-32VDC (ideal for PLC/microcontroller control) and 80-250VAC signals, ensuring broad compatibility with diverse control circuits.

• Silent Operation: The absence of moving parts eliminates audible clicking and electrical noise, perfect for sensitive or quiet environments.

• Extended Lifespan: Without mechanical wear, SSRs offer significantly longer operational lives compared to electromechanical relays, drastically reducing maintenance and replacement costs.

• Fast Switching & Zero-Cross Technology: Enables much faster ON/OFF switching and incorporates zero-voltage turn-on and zero-current turn-off, minimising electrical noise, voltage spikes, and extending connected load life.

• LED Status Indicator: A clear LED light provides immediate visual feedback on the relay's "ON" or "OFF" status, aiding quick diagnostics.

• Wide Operating Temperature: Functions reliably across a broad range from -40°C to 100°C, making it suitable for diverse industrial conditions.

• Enhanced Safety: "Protect Panel" design and adherence to IEC standards ensure reliable and safe operation, giving you peace of mind.

• Green & Efficient: Contributes to a more energy-efficient and environmentally conscious control system by reducing energy loss and waste.

Understanding Solid State Relays (SSRs)

A Solid State Relay (SSR) is an electronic switching device that, fundamentally different from an electromechanical relay, contains no moving parts. It uses semiconductor components (such as TRIACs, SCRs, or MOSFETs) to switch electrical power.

How it works:

At the core of many SSRs is an optoisolator (or optocoupler). This clever component electrically isolates the input control circuit from the high-voltage output load circuit using light. When a low-voltage control signal is applied to the input, an internal infrared LED illuminates. This light then triggers a photosensitive device on the output side, which in turn activates the high-power semiconductor switching components. This optical isolation ensures excellent electrical separation, enhancing safety and preventing interference between your control system and the powered load.

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

Important: Heat Dissipation

Solid State Relays, especially high-current units like this 40A model, generate heat during operation. Proper heat dissipation is absolutely critical for the SSR's performance, stability, and longevity. To ensure optimal operation and prevent thermal damage, this unit MUST be used with a suitable heatsink base or a finned heatsink. Please consult the provided heat dissipative power curve (if available) for specific heatsink requirements based on your current load and operating conditions.

Technical Specifications

• Product Type: Three-Phase Solid State Relay (SSR)

• Rated Current: 40 Amps (A)

• Output Current Range: 0.5A ~ 40A (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: 40mm x 110mm x 80mm

• Mounting: Panel Mount (requires heatsink)

Ideal Applications

This 40A Three-Phase Solid State Relay is an excellent choice for precise, reliable, and high-current control in a wide range of demanding industrial and commercial applications, including:

• High-Power Heating Elements: Industrial ovens, furnaces, large plastic moulding machines, and heating baths.

• Heavy-Duty Motor Control: High-current AC motors, pumps, and fans (ideal for frequent switching or soft start in industrial settings).

• Industrial Lighting Control: Switching large banks of industrial lighting.

• Power Supplies: High-capacity regulated power supplies and power factor correction systems.

• Large Packaging Machinery: Precise control of high-current heating and motion components.

• HVAC Systems: Controlling large industrial compressors, heaters, and fans.

• Process Control: General-purpose high-current switching in automated industrial processes.

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 and consider a generous safety margin.

Customer Reviews

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"Incredible Power & Durability for Our Furnaces!"

"Upgrading to these 40A SSRs for our industrial furnaces has been a game-changer. They handle the load effortlessly, and the silent operation is a huge plus in our facility. We've seen a noticeable improvement in system stability and far less downtime." — Operations Manager, Heavy Industry

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"Top-Tier Quality at a Fair Price"

"This SSR is exactly what you want for demanding industrial applications. The build quality is excellent, it runs smoothly, and the LED indicator is handy. It's truly a high-performance component that provides great value. Fantastic for anyone needing reliable high-current control." — Electrical Foreman, Construction, June 20

Frequently Asked Questions (FAQs)

Q1: Do I need a heatsink for this 40A Solid State Relay?

A1: Yes, it is absolutely essential. A 40A SSR generates significant heat during operation. An appropriately sized heatsink (either a heatsink base or a finned heatsink) is crucial to dissipate this heat effectively, ensuring the SSR operates within its safe temperature limits, preventing damage, and maximising 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 40A SSR be used for single-phase applications?

A3: While designed for three-phase use, a three-phase SSR can technically be wired for single-phase by using only two of the three output terminals, but it would be over-specified and likely not cost-effective. For single-phase applications, we generally recommend selecting a dedicated single-phase SSR for optimal performance and cost efficiency.

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) that can be generated during switching, thereby protecting both the SSR and your connected load and complying with stricter EMC regulations.

Q5: What types of loads is this 40A SSR most suitable for?

A5: This 40A SSR is ideal for both resistive loads (like high-power heating elements in industrial ovens, furnaces) and many inductive loads (like motors, transformers) due to its zero-crossing feature. When switching inductive loads, always ensure that the load's inrush current does not exceed the SSR's specified surge current rating for safe operation.

Experience superior, silent control for your high-current, three-phase power applications. Order your 40A Three-Phase Solid State Relay today!