The Zhaga Process
The Zhaga process uses a multi-phase approach to assure all ideas are shared openly so that specifications provide reliable interfaces while still maximizing the design freedom of LED technology. In the first phase, member companies present proposals for a product type for which they envision the need for standardization. There may be several proposals from different companies all for the same use applications. Then the members form a Task Force of volunteers who review each proposal and work to develop a specification framework that takes the best elements from each. The Task Force then asks the consortium members to vote whether they can form a Work Group to develop a specification.
Upon approval by the members, the specification begins to take concrete form. Once the specification seems set, the Work Group requests that manufacturers build prototypes to meet the draft specification. The prototypes are then reviewed for inter-operability and any issues found will be addressed with updates to the draft. Once the work group has a draft that is robust, they will submit it to the consortium members for a vote on whether to publish as a specification (Figure 1).
During the early period after the specification is approved, members may find improvement opportunities and will submit them to the work group for review prior to vote by the members. It is essential that any changes be compatible with earlier versions of the specification in order to reliably mate with products already available in the market. This provides assurance to the specifier community that the interfaces that come from Zhaga can be relied on in the future.
Approved Zhaga Specifications
Zhaga members have already approved several specifications. The first specification was approved in February 2011 for a socketable light engine with an integrated control gear (Figure 2) for down lighting applications. It is based on the Philips Fortimo Twistable, but has been adapted to meet regional requirements such as versions that can support universal input voltage (120/277V and 347V in Canada). Several companies provided prototypes and input to the development of the light engine and mating holder. The design creates a large thermal interface between the light engine and heat sink to enable the long-life and performance expected of LEDs, with replacement as easy as a quick twist.
The second specification that was approved is for an LED spotlight module with the control gear located in a separate housing. As can be seen from the prototypes in Figure 3, the physical size, and mounting of the modules is consistent, so that replacement in the field is simplified.
The third specification that Zhaga members approved is for a socketable spot light. The control gear of this spotlight engine is again located in a separate housing. Where the previously approved spotlight engine was meant for direct screw mounting, this new specification allows for simple twist replacement of the module into the holder.
As of the last meeting in November 2011, there were proposals for linear modules for both street lighting and indoor applications near completion.
Zhaga established a task force earlier in 2011 to study how the dimming behavior of LED Light Engines can be specified such that the light engines become interchangeable in their dimming behavior. The task force's first priority is phase cut dimming. Zhaga does not plan to create a Zhaga specification for dimming, but will cooperate with NEMA to establish a dimming interface standard that is suitable for LED light engines.
What Will Make Zhaga Successful?
Besides robust standards, Zhaga is putting into place both a mechanism to inform the user-public about these standards and also provide assurance through third-party testing that the products meet the requirements. In 2012, the Zhaga logo will begin to appear on numerous products to communicate compliance to Zhaga requirements.
About 80 participants from 40 companies from Europe, Asia, and North America continue to attend each Zhaga session. The Zhaga companies will continue their attention and sense of urgency throughout 2012 with the goal of creating peace of mind in the architectural and facility management communities that reliable LED products can be specified soon and will be available from many manufacturers well into the future.
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