The road to robust solutions … verify, then validate, validate, validate

Posted on: Tuesday, October 16th, 2018

At the dawn of ESDL, way before we solely focused on the energy management sector specializing in retro-fit energy management solutions in operational hotels (yes, operational, as in ‘welcoming guests, open for business’), the design effort of the tiny engineering team was on the development of bespoke voltage stabilizers. These ‘boxes’, as they were referred to by our clients, would stabilize a fluctuating power supply feeding sensitive electronic equipment. The grid at that time was hardly a paragon of reliability, let alone an exemplary quality power source.

One day, we were approached by the supervisor of a water-treatment plant for the delivery of some 30 voltage stabilizers rated at 5kW each. Specs were tight, but we were confident that we could deliver. Offer was submitted, duly accepted, and we were all set to go.

To cut to the chase, the design was verified in our little lab and all specs met to a dot. It was time to deploy the voltage stabilizers in the field.

We installed, tested, commissioned and handed over the whole lot. After a couple of days, I received a call from an agitated and irate client. He practically shouted peremptorily down the telephone line, “What the heck did you sell me?! These ‘boxes’ are driving my equipment nuts! Come over and fix the bl***** contraptions, now!”

Off we went, lumbering some test equipment along. Luckily, we soon determined what was causing our circuits to go berserk. On site, there was a large pump which was operated straight from the mains with no attempt at soft start. This large inductive load was powerful enough to jolt the grid, analogous to a large rock thrown at the centre of a small pond which causes substantial ripples to emanate from where the rock enters the water.

Imagine a leaf close to impact due to the large rock entering the pond, how it will bob furiously up and down before the rock-induced tsunami finally subsides. This is exactly what our circuitry was experiencing albeit in the electrical realm. A sudden jolt in the electrical supply, the grid, screwing up the operation of our circuits. Proper filtering cured the issue, luckily for us all.

All seemed well until a bemused supervisor called again, with more than a hint of exasperated sarcasm in his voice. “Your ‘boxes’ have been appropriated by spiders and other crawlies. Didn’t you know that your ‘boxes’ would be a magnet to all forms of creepy crawlies which tend to gravitate towards nooks and crannies? And, by the way, an intrepid lizard also got in, most likely to warm up its cold-bloodedness!” Bang went the phone.

A lesson learnt the bruising way. Verification (testing to verify that specs are met) of all products followed by controlled validation (testing in the field) became, and still is, the order of the day. Monitoring of deployed equipment, effectively continual validation, vouches for a robust system.

Failures are still likely to happen; however verification and validation mitigate failures to the point of insignificance.

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