Accelerate Production-Line Insulation Testing with the Hioki ST5520
In high-volume manufacturing, electrical safety testing must do more than confirm compliance. It also needs to keep pace with production takt times, reduce false judgments, and help prevent defective products from moving downstream. The Hioki INSULATION TESTER ST5520 is designed for exactly that role, combining fast insulation resistance testing with features that support stable, repeatable inspection in production environments. Hioki describes the ST5520 as an insulation tester for electrical devices and components that delivers pass/fail assessment in as fast as 50 ms, with freely configurable test voltage from 25 V to 1000 V in 1 V resolution.
One of the ST5520’s biggest advantages is speed. Hioki says the instrument is the fastest insulation tester in the industry and notes that testing can be completed in as little as 50 ms, with measurement speed selectable between Fast: 30 ms/time and Slow: 500 ms/time. Hioki also highlights significantly reduced post-test residual voltage discharge time, estimating a takt-time improvement of 990 ms under the sample conditions shown on the product page. For manufacturers focused on throughput, these gains can have a meaningful impact on line efficiency.
The ST5520 is also designed to reduce testing errors before they affect yield. Hioki includes a contact check function to verify proper contact with the device under test before measurement begins, helping prevent erroneous assessment caused by poor fixture or probe contact. The unit also includes a short-circuit check function, which applies a low voltage of 2 V to 4 V DC to test patterns before insulation testing in order to identify micro-shorting and stop potential defects from reaching the market.
From a measurement standpoint, the ST5520 provides practical flexibility for production users. It supports applied DC voltage testing with selectable ranges from 25 V to 1000 V, a basic accuracy of ±2% reading ±5 digits, and resistance ranges extending up to 4000 MΩ depending on the selected voltage range. Test duration can be configured from 0.045 s to 999.999 s, and internal memory can store up to 10 test setups including voltage, comparator limits, test mode, and timing conditions.
The instrument is also well suited to automated or semi-automated workflows. Hioki provides RS-232C as standard along with External I/O, while the ST5520-01 variant adds BCD output. The optional Switched Probe 9299 allows users to operate the tester while holding the probe, which can simplify handling in manual inspection setups. Hioki also specifically notes that the ST5520 is ideal for battery production lines, making it relevant for manufacturers seeking fast and stable insulation testing in EV battery and related electrical assembly processes.
For manufacturers seeking a practical solution for fast, repeatable insulation testing, the Hioki ST5520 offers a strong balance of speed, configurability, and production-line readiness. Its combination of rapid pass/fail assessment, contact verification, micro-short checking, and flexible integration features makes it a strong fit for modern quality assurance workflows.
To learn more, plesase Contact Us
