Reed Switch Life Tests

A reed switch life test is a critical procedure aimed at verifying the durability and reliability of reed switches under specific operating conditions involving voltage, current, and frequency. This test is considered destructive as it subjects the reed switch to continuous cycles of ‘make’ and ‘break’ operations until failure occurs or until the expected number of operations is completed.

During the life test, several key parameters are meticulously monitored:

1. Test Current and Voltage: The reed switch is subjected to its rated current and voltage, ensuring it operates within its specified limits.
2. Operating and Release Times: The time taken for the reed switch to close (‘make’) and open (‘break’) contacts is closely observed, typically monitored at intervals such as 1 ms or 2 ms.
3. Operating Frequency: Standard size reed switches are tested at frequencies ranging from 1 to 25 Hz, while miniature reed switches may be tested at higher frequencies up to 125 Hz, both at 50% duty cycle.
4. Contact Resistance: Throughout the test, contact resistance is monitored to ensure it remains below 5% of the test load during closure and does not exceed 500% of the test load upon opening.
5. Failure Criteria: The test identifies failure conditions such as excessive contact resistance, missed operations (failure to make or break), or physical welding of the reed switch contacts.

Setup for the life test involves configuring the test environment to apply the required load current and voltage. The reed switch is then subjected to continuous cycles of energizing (‘make’) and de-energizing (‘break’) the coil, with the rated voltage maintained across the open contacts during ‘break’ operations.

Output from the life test includes identifying failures such as ‘failure to make’ or ‘failure to break’, which are determined based on specific monitoring criteria applied shortly after energizing or de-energizing the coil. Contact resistance is also regularly monitored to assess the reed switch’s performance under load conditions.

Industry standards and protocols for reed switch life testing are crucial for ensuring product reliability across various applications, from automotive sensors to industrial controls. Manufacturers rely on these tests to validate design specifications and guarantee that reed switches meet or exceed performance expectations in demanding operational environments.