Hermetic relays in use

Hermetically sealed relays are a key component in the control and automation systems of modern aircraft due to their reliability and durability in harsh environments. They’re used in various critical systems within aircraft, including electrical power supply, power distribution, flap control, landing gear controls, fuel pump controls, de-icing systems, and fly-by-wire systems. They’re also used in automotives and in industrial equipment and telecommunication applications – everywhere there may be exposure to extreme temperatures, dust and dirt, and where long-term reliability is essential.

Typically designed to withstand a temperature range from -55 to +85 degrees Celsius, they’re  also suitable for high-voltage or high-power switching because of their ability to continuously conduct significant amounts of current at high voltages. They suppress contact arcing during switching, which can be a significant issue in high-voltage and high-power applications. They can maintain either a high-vacuum or a pressurized insulating gas environment, such as Sulfur Hexafloride (SF6), to suppress arc formation between contacts.

An advantage of some hermetically sealed relays is their double-make contacts design. This feature facilitates load sharing across two contact points, which can improve the relay’s performance and reliability.

Types and categories explained

Hermetically sealed relays come in various types, each engineered for specific electrical contexts and applications.

DC relays are geared towards systems running on direct current. They integrate a freewheeling diode within their setup, ensuring the relay coil is safeguarded against potential voltage spikes during deactivation. This diode provides a safe path for inductive kickback, a common phenomenon in DC circuits. Characteristically, these relays excel in managing DC loads, offering reliable switching functions essential for direct current operations.

AC relays, on the other hand, are built to function with alternating current. These relays feature laminated cores designed to mitigate eddy current losses – unwanted byproducts that occur as the current shifts direction. With a focus on the nuances of AC, such as phase and frequency adjustments, AC relays are pivotal for controlling AC power in various settings, with the added benefit of enhanced efficiency thanks to those laminated cores.

Magnetic latching relays stand out for their use of permanent magnets. These components retain the relay’s open or closed state without a constant power supply, a clear energy-saving advantage. With just an electrical pulse, the state can be changed, and then maintained by the magnet. Applications where power is scarce or where maintaining a state during a power loss is crucial, such as safety or memory functions, utilize these relays because of their dependability and low energy consumption.

High Frequency (RF) relays are suited to scenarios where radio frequency signals are the norm. They’re adept at switching these high-frequency signals with negligible loss, critical for maintaining clarity in RF communication and high-speed data lines. These relays stand apart for their superior isolation and minimal insertion and return losses, ensuring that RF applications function at their peak without interference that could degrade signal quality.

Why choose Leach relays?

Leach relays are a superior choice due to our commitment to excellence in manufacturing and testing. Our process is rigorous, undergoing constant reviews for improvement, ensuring the highest quality and reliability.

Leach relays come hermetically sealed, built and tested to MIL standards (MIL-PRF-83536, MIL-PRF-6106, and MIL-PRF-83726). The leak rate defines the number of years it will take for the inside gas of the backfill sealed relay to leak out and the inside gas to be replaced by the outside atmosphere. A smaller cc/sec leakage means the seal will last longer. Some Leach relays have fine leakage rate of no more than 1×10-8 cc/sec such as KXDL and some relays have gross leakage rate of 1×10-6 cc/sec. This low leakage extends the shelf life of our parts.

Each relay undergoes a detailed three-step testing process to verify its leak rate, surpassing the industry standard of 1×10-6 Atm cm3/s of air per MIL-PRF-6106 & MIL-PRF-83536 requirements with a more stringent self-imposed standard of 1×10-8 Atm cm3/s. We ensure every component is 100% tested throughout the manufacturing process and use only the highest quality materials for our sealing process. 

Our portfolio

Leach Corp’s portfolio of hermetically sealed relays addresses a wide array of high-reliability power switching needs. Our products have a wider temperature range for extreme environments; we push the limits from -70 to +125 ℃ on many. From the X and XA Series relays, perfect for resettable power control and communication circuits, to the XL and YL Series with their latching capabilities crucial for maintaining stable states during power outages, each model serves a unique purpose. The Y Series offers flexibility with multiple switch options, while the YA Series suits AC power systems. For demanding industrial contexts, the KD series stands out with its higher current handling. High-quality, hermetically sealed products include 50A to 300A, DC or AC. All these relays are remarkable for their robust design, ensuring consistent performance and rugged reliability.

Visit our website to find out more.

Nini Ayon, Manufacturing Engineering Director at Leach Corp, brings an 18-year track record in engineering, notably with L3Harris. Her UC San Diego education and APICS certifications underpin her expertise in power distribution systems.

Celebrated for her Six Sigma success and team development, Nini is also an awarded community leader and avid volleyball player.