High-Performance Thermal Compound (2-Pack) Efficient Heat Dissipation - Versatile Solution for Including SSR40DA, SSR40AA, SSR25DA, SSR25AA - Extend Component Lifespan with Exceptional Thermal Paste

Easy to implement and works as advertised. The screw terminals seemed a bit small, but usable.A good SSR for many projects.

Wanted to give the 40A relay a try for some projects that will draw 30-40 amps. The screw covers are definitely a nice touch. One thing I did notice while testing this relay is there is around 14vac leakage to the heat sink surface. You will want to have a good ground to whatever heat sink surface you will be attaching this to in order to prevent further buildup of stray voltage. I have not observed this with higher quality SSR's. Other than that, it works well as a general purpose SSR.

The Industrial 40A DC to AC Solid-State Relay is an essential component designed for efficient and reliable DC-AC switching in various industrial applications. Offering a blend of robust performance and practical design features, this solid-state relay (SSR) is particularly suitable for projects requiring precise control over high-power AC loads from a DC signal. This review will delve into its specifications, performance, design, and overall utility, providing insights into its suitability for projects like Zero G conversions and similar high-demand applications.Specifications and PerformanceInput Voltage: The SSR supports a DC input voltage range of 3-32 VDC, making it versatile for different control signals in industrial environments. This wide range allows it to be compatible with most low-voltage control systems.Output Voltage: With an output capability of 24-380 VAC, this relay can handle a broad spectrum of AC loads, catering to a variety of industrial requirements. This feature ensures the relay's compatibility with a wide range of equipment and machinery operating within this voltage range.Current Rating: The maximum peak current rating of 40A, with a continuous operational capacity of 20A, signifies the relay's ability to manage substantial power loads. This makes it particularly useful for applications that require high power handling capacity without compromising performance or safety.Design Features: Equipped with terminal covers and a transparent cover, the relay is designed for both safety and ease of monitoring. The terminal covers provide protection against accidental contact, while the transparent cover allows for visual inspection of the internal components, facilitating easier troubleshooting and maintenance.Performance in ApplicationIn the context of powering a Zero-G conversion project, the relay's robust performance and reliability are of paramount importance. The ability to switch AC loads effectively using a DC control signal is crucial in applications that demand precision and stability. Users have noted that the power-up process is promising, indicating a smooth and reliable operation from the outset. The solid-state nature of the relay ensures silent operation, minimal wear and tear due to the lack of moving parts, and faster switching times compared to mechanical relays, enhancing overall efficiency and longevity.Design and UtilityThe industrial-grade design of the 40A DC to AC Solid-State Relay is tailored for durability and long-term use in challenging environments. The inclusion of terminal and transparent covers not only adds a layer of safety but also enhances the user experience by simplifying installation and maintenance. This attention to detail in design reflects an understanding of the practical needs of industrial users.ProsHigh current rating suitable for demanding applications.Wide input and output voltage ranges offer versatility.Safety features like terminal covers protect against accidental contact.The transparent cover enables easy monitoring and maintenance.Solid-state technology ensures reliability and longevity.ConsThe continuous current rating of 20A might limit its use in applications requiring sustained high power beyond this threshold.Depending on the application, additional cooling measures may be necessary to manage heat generation in high-power or extended-use scenarios.ConclusionThe Industrial 40A DC to AC Solid-State Relay offers a compelling mix of performance, safety, and design features for industrial applications requiring efficient DC-AC switching. Its ability to handle high-power loads, combined with user-friendly design elements, makes it a valuable asset for projects such as Zero-G conversions. While considerations around continuous power handling and heat management may influence its application in certain scenarios, the relay's overall reliability and efficiency make it a worthwhile investment for those in need of a robust switching solution.

I've used Fotek SSRs for at least 10 years now in a lot of AC powered projects. Here's a picture of my solder reflow oven where one controls the heating elements and the other the exhaust fan. What is special about these (besides being able to control AC power from a microcontroller) is that they incorporate zero crossover switching (I didn't notice this in the description). This is really important for cheap AC power control because the alternative is that you have to know where the AC wave is and switch it at the right moment. These SSRs switch the power on or off only when the AC wave is at 0 volts (when it is crossing over to the other side of the sine wave). For resistive loads like heaters this really doesn't matter. But for inductive loads (think motors) switching at different parts of the AC wave can cause the motor to overheat as well as stress the components. These SSRs take care of this problem for you so even if you are pulsing the fan at 10Hz you should still be ok.Anyway...enough rambling. If you need to control AC power from a microcontroller and you don't want the click clack of one of those mechanical relays this is definitely the way to go. Most of the time I did not need to use a heatsink but it really depends on how much amperage you will be pushing through this. If it gets hot though...do NOT run it without one since you will inevitably damage the SSR. Most of the time SSRs always seem to fuse in the open state...so avoid that all together and use a heatsink if needed.

This unit works as one would expect. Given the limited nature of what a solid state relay does, its hard to say "hey, this is a five star unit!" or "this is garbage, one star!" if it works.That said, I'm giving this three stars for the simple reason that other identically-spec'ed SSRs at the exact same price come with a heatsink, and these do tend to get hot and will be unreliable if they aren't kept cool. Even though the listing didn't mention it, I was surprised it didn't come with one, as I'm not sure I've ever bought one that didn't. Thankfully I had a spare in a part bin. But its something to be aware of.