Automated End-of-Line Test System for High-Power Load Banks

Project Summary

A manufacturer of customized power solutions engaged Cyth Systems to design and deliver a fully automated end-of-line test system for validating high-power load banks across its full product line. The solution synchronizes switching and test points across multiple high-voltage configurations and current load levels, with hardware-triggered interlocks to protect operators throughout live, and sharing standardized test software across their catalog of load bank models.

System Features & Components

• NI PXI measurement system operable up to 1200A and architected to scale up to 2500A+ in next-generation load banks

• Automated voltage switching across 600V, 480V, 240V, and 208V, with interlocks preventing hazardous energy paths

• Hardware-triggered safety interlocks that abort the test sequence upon over-condition, with a safety shield removing operator exposure during live-power testing

• Over 1,200 tested wire terminations integrating measurements, relays, and interlocks into a single system

• Flexible, single-sequence test software that replaces per-model programming and scales across the load bank portfolio

• Automated report generation produces a complete digital test record for every manufactured unit

Outcomes

• Operator physical exposure to high-power eliminated testing eliminated, with hardware-triggered interlocks replacing manual live-power intervention

• Unit-to-unit repeatability increased through synchronized measurement architecture, removing settling-time variability and simplifying data correlation

• The same test software scales to next-generation load banks rated up to 2500A, without requiring a new sequence to be built for each model.

Technology at-a-glance

• NI PXI platform for automated measurement, control, and relay switching

• LabVIEW

• NI TestStand

Load Bank Validation at Megawatt Scale

Load banks apply controlled electrical loads to characterize and validate efficiency of backup generators before they go into service. Building and testing these units at a megawatt scale means each unit leaving the factory must be traceably tested at potentially lethal voltage and current levels.

A power electronics manufacturer with both standard and custom solutions with long field lifespan requirements partnered with Cyth Systems to replace their manual, high-risk, end-of-line test process with a fully automated system built on NI PXI, NI TestStand, and LabVIEW.

Manual Load Bank Testing Exposed Operator and Audit Risks

Previously, end-of-line test for every single load bank required that an operator manually applied and measured live electrical loads, using handheld multimeters and clamp-on current transducers. The process exposed test operators to hazardous conditions: physically plugging and unplugging cables, flipping switches by hand, and standing near the unit during energized testing, with arc flash events occurring on occasion.

Live power settling times resulted in readings under identical test conditions to differ from each other. This made measurement repeatability difficult to establish and challenging to defend under audit. Manual testing, combined with a lack of defensibly correlated data, limited both operator safety and the manufacturer's ability to prove consistent quality across its product line.

Automated Load Bank Validation with NI PXI and TestStand

The power electronics manufacturer reached out to Cyth Systems for help automating their testing. Cyth's engineering team focused on designing safety directly into the system architecture rather than adding it as a secondary layer, eliminating manual intervention for any step operators performed manually.

• Every measurement executes at the same point in the program flow on every run, removing the settling-time variability that made manual readings inconsistent.

• Operators run the full test from behind a safety shield, without exposure to live high-power circuits.

• Standardized test software, built using NI TestStand and LabVIEW, with model-specific preconditions, eliminates the need to build and validate a test sequence for each load bank model.

• Standardized test software approach lowers cost of test, by reducing the long-term software devleopment and maintenance effort as the manufacturer's product line grows.

Automated Testing Delivers Safety and Repeatability

• Operator safety improved through automated high-power testing and interlocks to remove reliance on manual intervention during energized test conditions

• Data reproducibility was standardized across the full product line, with every measurement captured at the same point in the test sequence.

• Traceability and quality assurance for every manufactured unit was achieved through the automatic generation of complete digital test records.

• Manufacturing throughput and product quality increased, replacing a tedious, manual process with automated sequencing.

The manufacturer moved to duplicate the test system to expand their operational capacity, adding a second station built on the same NI PXI and NI TestStand platform. The new system covers the same full range of load bank models using the same software, extending the automated test throughput and data consistency across manufactured units.