Tuesday, Feb 25, 2014
The term converter was used to describe the component that converts the standard 230V AC into the regulated DC that the LED luminaire requires. Two types of converters were described: the ‘Constant Voltage’ and the ‘Constant Current’. The main difference between these is that constant voltage is mostly used for linear LED products whereas constant current is mostly used for single point light sources such as downlights.
Oliver made us aware that one issue with matching the converter to the luminaire is that different manufacturers specify a range of varying details to describe the functionality of their product. Of these details, the three that are important for selecting a converter are: Current, Power and Voltage. Operating Current for LEDs is usually recorded in milliamps, the most common values of today’s LEDs being 350mA, 500mA, 700mA, 900mA, 1050mA, 1200mA, 1400mA and 1750mA. Finding the appropriate solution involves selecting a converter with matching details within the product catalogue. Another selection criteria may be the product’s ability to be dimmed by either DALI or DSI.
The catalogue will give additional specification data including earth leakage current. Oliver noted that when designing circuits, it is recommended that the total earth leakage current does not exceed 1/3 of the rated tripping current of the RCD as they are designed to trip at any level greater than 50% of their maximum rating.
We were informed that there are many converters being sold with LED luminaries that are not compliant with, or tested to, the relevant standards. The standards worth looking out for include the the Regulatory Compliance Mark (RCM, shown below) that replaced the C-Tick from the 1st of March 2013, the AS/NZS61347.1 & IEC 61347.2.14.
This presentation on converter technology left those present with the tools to select the correct converter for the luminaire and a greater understanding of the surrounding issues and future developments of this technology.