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16-Ch, 440VAC Multiplexer



Skills Chart
Teaming Specifications, Schedules, Budgets, Partnering with local manufacturers
Technical Power Electronics, Digital Electronics, AC Motor Controls, Safety conventions
Software Electronic Design Automation (EDA) tools (Circuit-board layout)
Hardware System & circuit design, layout, component selection, prototyping, testing


The photo shows a Custom Industrial Motor Control assembly.     A big bank of solid-state switches that control 440VAC power.

It contains 16 separate channels, with indicator lamps, fuses and "fuses blown" neons for each.

It's designed to interface mechanically and electrically with an existing Programmable Logic Controller ( PLC ).

[A 440VAC switch bank]


The design goal was a switch-matrix to extend the functionality of an existing Omron© PLC used in plastic injection-molding equipment.

Previous versions of this assembly were prone to catastrophic failure in the dirty industrial environments where they're used.   Some had failed earlier, during commissioning.   They would overheat or arc & explode.   Very dangerous.   And they smelled bad.

Our Client contacted us because they wanted the design reviewed by a Licensed Engineer.   They had learned that not all folks who design circuits and circuit boards know what they're doing; this was to be their third attempt.   Production was at a standstill and tempers were short.

The assembly had to perform correctly and be retrofittable to existing installations.   (You don't just unplug a huge injection molding machine and ship it back to the factory for service...)

They also wanted to incorporate somewhat different components, to alleviate certain other issues of fit & function.

We examined the failed assemblies, worked with our Client to establish appropriate Specifications and developed a new design.

Our Client outsources this assembly to a local Turn-Key Manufacturer (which referred us), so we included the vendor's Production folks early in the design, and worked with them to ensure buildability.   After all, they know as much about their jobs as we know about Electronics.

We created the circuit-board layout and mechanical drawings, reviewed the artwork before fab and monitored the first-article Production closely, which led to some procedural fine-tuning but no big "gotchas".

The new design has now been in Production for more than a year with no failures and no complaints!




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