Inductor for airport runway lighting

Inductors from the customer's previous manufacturer would sometimes overheat in the application, causing failures in the lighting along airport runways. The original design was fixed and could only be changed incrementaly for cost reasons, so any fix had to work within the basic design — a common challenge for custom magnetic components in demanding, cost-sensitive applications.

Key challenges

• Field failures — overheating inductors led to defective runway lighting
• Fixed, third-party design — the basic construction itself could not be altered so much
• Cores near saturation — the cores operating close to (soft) saturation
• Uneven current sharing — two parallel inductors, with the one closest to saturation drawing a disproportionate share of the AC current
• No margin for cost increases — any change that added cost was out of scope

With the base design fixed, we solved the issue through manufacturing precision rather than redesign:

• Repeatability — we significantly optimised the production consistency to get near identical components in a produced batch.

• Matched pairing — every inductor was tested individually and sorted by its measured properties, so only the best well-matched units were paired for use in the application

Every inductor went through the same process: produced as consistently as possible, tested individually, and packed in matched pairs before shipment — all without changing the basic design.

The inductor is used in an inverter that converts power at 50/60Hz. Its role is to smooth out the fast electrical fluctuations that occur alongside that process. The shape and construction of the coil itself had already been fixed by the customer beforehand, and stayed that way — that choice was, and remained, up to the customer.

• Higher efficiency
• Better thermal performance / less heat generation
• Lower losses
• Longer lifespan
• Better reliability