Among the major types of HID lighting, Sylvania mercury bulbs
have been used for decades and still are in use for many fixtures today.
The technology involved in this lighting is similar to fluorescent
lighting. An arc is established between two electrodes in a gas-filled tube
which causes a special vapor to produce the light you see. Unlike fluorescent
bulbs, this light does not need a coating of phosphors in order to produce the
light, the light comes from the arc itself and creates a tremendous amount of
light. Although it doesn't need the coating to produce light, many times
it is used with the coated version of the lamp. In the past, manufacturers
tried to make the color more warm by using a coating on the inside of the lamp
and that coating is usually referred to as deluxe white.
All the major manufacturers like Sylvania, produce mercury vapor light
bulbs in all kinds of wattages and sizes. It has an excellent construction and has been a top
performer among the other brands. Be aware that like fluorescent bulbs,
these also have a specific ballast that is used for each wattage. You
can't change from one wattage to another even if the bulb might fit in the
socket. Most of the time the ballast is a core and coil type which is very
heavy. The ballast will be clearly labeled as to which type of lamp it operates.
So all you have to do is remove the covering and look to the label for lamp
operation. If you don't
the correct lamp and ballast combination you can reduce both
lamp and ballast life and cost yourself more money in maintenance. A lamp of 100 watt cannot be swapped with a 250 watt and so on. Keep
this in mind when changing lamps or changing a ballast with these special lamps.
These were a popular lamp many years ago for warehouses and gymnasiums because
of the white color. With the advent of metal halide lamps, many people
switched to those because they were more energy efficient and didn't lose light
output like mercury bulbs did. They come is various
configurations such as mogul base or medium base and an egg shape bulb or as a
R40 flood light. In some cases, it's all that can be used.
Some people wonder about the color of these lamps. Is
there a color shift from different manufacturers? The answer
is a definite yes, and there can be a different color between manufacturers and various
lots. Mercury vapor light bulbs are also notorious for getting a slight greenish color
at the end of it's life. The unfortunate thing is that they can seemingly
last forever in that state and people will leave them in place because it's lit.
But the truth is, it should be replaced when that happens. Be aware that color can shift over
time and the only way to get back to the original color is to replace the lamp.
It's sometimes a sign of end of lamp life. In most architectural specifications,
mercury bulbs are being replaced with metal halide, the HID lamp of choice for almost all
high light output applications.
With the advent of more efficient lamps, other mercury vapor bulbs are
being specified less often.
Some of the most common varieties of mercury vapor light bulbs are as
H37KC-250/DX and the
H33GL-400/DX. The second number in these codes
pertains to the wattage of each lamp. Of course, there are other far less common
wattages, shapes, and sizes available. The various manufacturers have different
names for their product, but we stock the Sylvania mercury vapor lamps. We
have a large inventory of these lamps for nearly every type of
light fixture in the field. If you need help identifying a bulb, our customer service representatives can help you determine what you have.