Zero-Crossing Solid-State Relays (SSRs): The Ultimate in Silent & Precise Control

Upgrade Your Control System with Unmatched Reliability

Traditional mechanical relays, with their constant clicking and moving parts, are prone to wear and eventual failure. For today's demanding industrial applications, you need a control solution that offers speed, silence, and exceptional longevity.

Our range of Zero-Crossing Solid-State Relays (SSRs) from 25A to 60A provides a superior alternative for your industrial control needs. These relays feature no moving parts, ensuring a near-infinite operational lifespan and completely silent performance. They use advanced optical semiconductors for opto-isolation, providing a safe and reliable bridge between your control signal and the load.

Engineered with zero-voltage turn-on and a built-in snubber circuit, our zero-crossing SSRs are the preferred choice for accurate and stable control. They eliminate electrical noise, making them ideal for use with sensitive equipment like PID temperature controllers and other precision devices. While they may cost more upfront than a mechanical relay, their incredible durability means they will outlast traditional units many times over, saving you significant time and money on maintenance and replacements in the long run.

Key Features & Benefits

• Zero-Crossing Technology: Minimises electrical noise and interference by only switching the load ON or OFF when the AC voltage is at or near zero. This feature protects both the relay and the connected equipment.

• Zero-Wear, Silent Operation: With no moving contacts to wear out, these SSRs offer a virtually unlimited lifespan. Their silent operation makes them perfect for noise-sensitive environments.

• High-Level Opto-Isolation (4000 VAC): Electrically isolates the low-voltage control circuit from the high-voltage load, protecting your sensitive control systems from voltage spikes and ensuring enhanced safety.

• Built-in Snubber Circuit: Provides protection against voltage transients and spikes, increasing the reliability and lifespan of the relay and the connected load.

• Versatile Mounting Options: Designed to be panel mountable and DIN mountable, allowing for flexible and secure integration into new or existing control panels.

• Wide Compatibility: The control input is TTL/CMOS compatible (sink mode) and features reverse voltage protection for both DC and AC inputs, ensuring seamless integration with most control systems.

• Safety Cover Provision: Includes a provision for a safety cover, adding an extra layer of protection for terminals and wiring.

• NO/NC Output Configuration: Available in both Normally Open (NO) and Normally Closed (NC) output configurations to suit a variety of application requirements.

What is a Solid-State Relay (SSR)?

A Solid-State Relay (SSR) is an electronic switch that performs the same function as a traditional electromechanical relay but with no moving parts. Instead, it uses semiconductor devices to convert a small electrical signal (the control input) to switch a much larger load.

The core technology behind this is opto-isolation, where a light source (typically an LED) is used to activate a photosensitive device on the output side, completely isolating the two circuits. This ensures that the control system and the load circuit are not physically or electrically connected, providing superior safety and protection against electrical noise.

Our SSRs are of the zero-switching type, which is the most common and effective form. It ensures that the relay turns ON or OFF only when the AC current or voltage passes through zero, thereby eliminating the sharp electrical spikes and interference that can occur with random or phase-angle switching.

Important: Sizing & Heat Dissipation

Due to the heat generated during operation, it is a critical best practice to oversize your Solid-State Relay by a factor of two times the actual load. For example, if your load draws 25A, you should select a 50A or 60A SSR. This ensures the relay operates well within its safe limits and significantly extends its lifespan.

Furthermore, SSRs must be used in conjunction with a suitable heatsink to dissipate this heat. Failure to use an appropriately sized heatsink will lead to overheating, premature failure, and can void the product warranty.

Technical Specifications

Ideal Applications

These zero-crossing Solid-State Relays are the perfect choice for high-reliability, precise, and high-cycle switching applications, including:

• Temperature Control: Ideal for use with PID temperature controllers in ovens, furnaces, and heating systems.

• Industrial Automation: High-cycle switching for motors, solenoids, and valves.

• Lighting Control: High-power lighting systems where quiet operation and fast switching are required.

• Heating Systems: Control of heating elements in commercial and industrial equipment.

• Power Supplies: Switching power supplies for sensitive electronic equipment.

Experience the difference that silent, precise, and reliable control can make. Select the right amperage for your application and upgrade your system with a zero-crossing Solid-State Relay today!