35 mm × 3.5-mm height
50 mm × 7.2-mm height
The Zhaga Consortium has announced publication of Book 11 covering 35-mm-diameter
LED modules intended for applications such as spotlights and similar luminaires. Book 11
becomes a part of a set of related specifications for round modules with Book 3 describing
50-mm modules and Book 10 describing 75-mm modules.
Zhaga is an industry organization that is seeking to simplify the supply chain for solid-state lighting (SSL) manufacturers by establishing standards for interchangeable LED
While Books 11, 3, and 10 all define a fixed
mechanical size for LED modules, the Books
also offer options in terms of the size of the
light-emitting surface (LES) or source size
characterized by category. Book 11 includes
LES 6. 3 ( 4. 5 to 6. 3 mm), LES 9 ( 6. 3 to 9 mm),
and LES 13. 5 ( 9 to 13. 5 mm).
Book 11 differs in two ways from the earlier
Zhaga books. The organization said it is the
first Book “to describe an LED module, rather
than a complete LED light engine.” That is a
subtle distinction because Book 3 and Book 10
both require an external driver, or what Zhaga
calls electronic control gear (ECG), to combine
with an LED module to compose an LLE. Books
3 and 10 define the required ECG via references
to form factors.
Modules defined by Book 11 will also require an external ECG, but Book 11 doesn’t specifically cover drivers. Zhaga is also working on a new Book 13 to define drivers that can be
used with Book 11 modules. And developers working with Book 11 can rely on the drivers
defined in Book 1 while Book 13 is under development.
Book 11, meanwhile, is also the first Zhaga Book to require that the modules comply with
the LEDset specification that has been developed by another industry organization, the Mod-ule-Driver Interface – Special Interest Group (MD-SIG). Member of the MD-SIG include BAG,
Helvar, Osram, Panasonic/Vossloh Schwabe, Philips, TCI, and Zumtobel/Tridonic. The LEDset specification defines the electrical interface between the driver and module, including
the ability to set the current level produced by the driver either by an external current-set
resistor or a resistor that can be optionally integrated in the module. ◀
48,000 LED street
lights installed in
The US Department of Energy (DOE) has
published a new report — “Restoring
Detroit’s Street Lighting System” —
that provides an update on an LED
street light project announced last year
and that the DOE has assisted with in
a hands-on manner ( http://bit.ly/1xik
GWu). The project is about two-thirds
complete and will ultimately include
installation of 65,000 SSL luminaires.
The project was intended to restore
street lighting in Detroit, save energy,
and boost the local economy.
The project began in earnest back in
2013 as the city declared bankruptcy. The
city had 88,000 legacy lights at the time
and around half were operational. The
failed lights in some cases just had failed
HID lamps or ballasts, but in others vandals had stolen wire and transformers
from the poles in the cash-strapped city.
Michigan’s governor appointed an
Emergency Manager who created a Public Lighting Authority (PLA) that began
to consider how to address the problem.
Indeed, the financial burden was even
bigger on the city than it might seem
because based on an unmetered tariff,
it was paying for energy on the working
and non-working lights in the inventory.
With so many lights out, projections
of the cost of new lighting and a comparison with the existing system had
to be based on an assumed scenario
in which all of the lights were working
properly. The PLA and DOE speculated
in the analysis that LED installation
would save almost $3 million in electricity annually and more than 45 million k Wh of electricity.
The PLA knew from the start that a
couple of aspects of the project would
be unique. The street light system infrastructure would have to be as much a
part of the project as the luminaires
because of deterioration and vandalism.
Moreover, the city would » page 16
Zhaga publishes Book 11 for
35-mm spotlight LED modules