New MH gear flexibleand energy-efficent
New MH gear flexibleand energy-efficent
Several years after Osram presented their metal-halide lamps with a ceramic
burner they have finally launched an electronic ballast to go with the
lamp. As reported in IAEEL
Newsletter 3-4/97, Osram couldn't use their electronic high frequency
(1 kHz) ballast for the ceramic lamps. This is because an acoustic resonance
phenomenon may occur with the ceramic-burner lamps at high frequencies
and damage the lamp. Philips solved this problem early by opting for an
electronic ballast with an operating frequency below 200 Hz.
Osram's new Powertronic Universal ballast operates, just like the
Philips unit, on 130 Hz and produces a square-shaped wave form which reduces
flicker to a minimum. Osram reports that the modulation is only 7-8 percent
for lamps operated on the new ballast.
Another important feature is that the ballast, like its Philips counterpart,
will drive all current 70W MH lamps in their product line: single- and
double-ended as well as screw-base in both ceramic and quartz versions.
The electronic components are optimized so that losses are only 6W, compared
to 10-13W for conventional units. For a 70W lamp, this ballast improvement
corresponds to an energy savings of about 7%. It is difficult to make
an exact comparison between ballast from the two suppliers, since actual
lamp wattage may not correspnd to nominal values. Philips, for instance,
says that their 70W lamp has an actual power of 73W, and the ballast have
additional losses of 7W.
The new electronic ballasts have no sealing compound (or “potting”).
This has reduced the weight of the ballast, but Osram also claims that
eliminating the sealing compound will make the ballast more reliable.
The Osram ballast employs a new electronic starter called IGBT. This unit
has similarities to a transistor, and Osram claims that it will make the
start up of any lamp more reliable and considerably increase lamp life.
Nils Borg