Archive for April, 2012

The Test Mule passes 12 months in continuous operation.

In the process of building Tasca, there has been numerous iterations, prototypes in metal and plastic, tests to failure, drop and impact tests, electrical and electronic tests, and lighting application tests. As we found what worked, and what didn’t, and collected tooling for components, like the heat sink, I build the first functional products, using production level components. The first one made was what we affectionately call the Mule. It has been lighted 24/7 for one year as of the end of March, or a total of 8,841 logged hours to date. In that time it has been tested under operating conditions, attached to the side of a milling machine head, sprayed with lubricating and cleaning fluids, dropped, dunked, draped with rags under high ambient conditions, and frozen. As shown in the images here, this head has had a few hoods and shields attached to test effectiveness, and the mounting adapter has been changed a couple of times as I’ve experimented with the machined attachment hardware. This head has a thermocouple lead installed, so at any time I can plug it in to see what the temperature of the LED is, while there has been numerous output tests to check lumen depreciation, which has been less than 1% to date, right on track with the LM80 data for the LED (Bridgelux ES array).

This fixture has also been used as a baseline for testing the finished product as it has evolved. For example, we found that black anodizing og the heat sink lowered the LED temperature under identical operating conditions by as much as 10°C. We have also evolved the use of spring washers in the hinge, made small adjustments in the use of fasteners, and added the disconnect power connection to replace the Heyco cord entry – all found from actively working with the product and improving every detail. (more…)