Transcript Presentation_Electrical_ballasts_Mr ZALPYSx

Aleksas Žalpys
Chief State Inspector
Products Control Department
STATE NON FOOD PRODUCTS
INSPECTORATE
UNDER THE MINISTRY OF ECONOMY OF THE
REPUBLIC OF LITHUANIA
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An electrical ballast is a device intended to limit the amount
of current in an electric circuit. A familiar and widely used
example is the inductive ballast used in fluorescent lamps, to limit
the current through the tube, which would otherwise rise to
destructive levels due to the tube's negative
resistance characteristic.
Ballasts vary in design complexity. They can be as simple as a
series resistor or inductor, capacitors, or a combination thereof or
as complex as electronic ballasts used with fluorescent
lamps and high-intensity discharge lamps.
Ballasts limit the current through an electrical load. These are most often used when
a load presents a negative (differential) resistance to the supply. If such a device
were connected to a constant-voltage power supply, it would draw an increasing
amount of current until it was destroyed or caused the power supply to fail. To
prevent this, a ballast provides a positive resistance or reactance that limits the
current. The ballast provides for the proper operation of the negative-resistance
device by limiting current.
A gas-discharge lamp is an example of a device having negative resistance, where
after lamp ignition, the increasing lamp current tends to reduce the voltage
"dropped" across it, (if it is in series with other circuit elements). Ohms Law states
R = V / I so R is effectively decreased if V decreases or stays constant while I
increases. The resistance is lowered by increases in current which is opposite to the
normal effect and therefore called "negative" resistance. In some cases a simple
series current limiting reactor (inductor) is sufficient to act as a ballast for a lamp.
Ballasts can also be used simply to limit the current in an ordinary, positiveresistance circuit. Prior to the advent of solid-state ignition, automobile ignition
systems commonly included a ballast resistor to regulate the voltage applied to the
ignition system.
Series resistors are used as ballasts to control the current through LEDs.
The indoor lighting is a combination of external daylight and artificial lighting,
which should be considered both in building design and in lighting design. Results
of those will have in turn impact on mechanical design. The good energy efficiency
comes from good understanding of user requirements and design applications.
Proper surface colours and reflectance, light sources, luminaire and lighting controls
are essential for user’s satisfaction, well-being, productivity and energy efficiency.
The European Commission has introduced The Energy Labelling Directive, which
is a legislative framework for requirements and performance levels for standard
lighting bulbs The directive requires that products be labelled to show their energy
power consumption in such a manner that it is possible to compare the efficiency
with that of other makes and models. Energy rating to classes A – G are used, where
the class A represents the best practice in the market and class D the average energy
use. CE-marking a product is not permitted unless it complies with the directives,
which apply to it.
The European Standard EN 62442 fixes the measuring methods for the total input
power of the ballast –lamp system. Using this European Standard as a basis,
CELMA (the European Federation of the National Association of the manufacturers
of luminaires, control gear and lampholders) has fixed both energy classes and limit
values for the ballast-lamp combination of the common fluorescent lamps. The
CELMA “Energy Efficiency Index” system contains 7 classes: A1, A2, A3, B1, B2,
C and D. The guideline is valid for mains-operated ballasts for fluorescent lamps.
The EEI system comprises of the following lamp types:
Tubular fluorescent lamps T8
Compact fluorescent lamps TC-L, TC-D, TC-T and TC-DD
The International Standard IEC 62442-1:2011 defines a measurement and
calculation method of the total input power for controlgear - lamp circuits when
operating with their associated fluorescent lamp(s). The calculation method for the
efficiency of the lamp controlgear is also defined. This International Standard
applies to electrical controlgear lamp circuits consisting only of the controlgear and
the lamp(s). It is intended for use on a.c. supplies up to 1 000 V at 50 Hz or 60 Hz.
Different maximum values of system power input including the light source and the
ballast have been defined for common lamp types. As an example the seven EEI
classes for a 36 W T8 (T26) fluorescent lamp are the following:
Class
D
C
B2
B1
A3
A2
A1
Description
magnetic ballasts with very high losses
magnetic ballasts with moderate losses
magnetic ballasts with low losses
magnetic ballasts with very low losses
electronic ballasts
electronic ballasts with reduced losses
dimmable electronic ballasts
System power
> 45 W
≤ 45 W
≤ 43 W
≤ 41 W
≤ 38 W
≤ 36 W
≤ 38 /19 W (at 100% -25%)
According to European Directive 2000/55/EC today only the classes A1 though B2
will be valid in of the voluntary CELMA EEI rating.
There are choice of several types of light sources with different features for the
different lighting applications. When selecting the bulb, attention should be put a.o.
in light colour, colour reproduction, energy efficiency and service life. Also
controllability and operating temperatures of the bulb are important. Light output of
light sources vary, among others, with type, size, voltage and operating hours. Light
output (lumen/W) of some types and sizes are shown in table below. Lighting
efficiency vary very much by the type and in some degree by the size. Some of the
products have the CE energy rating markings to ease the selection.
Most of the new energy efficient lighting systems have been designed to operate the
Standard 40-watt F40 fluorescent lamps. The lighting industry has introduced a 34watt F40 krypton-filled lamp that will draw less power from the same lighting
equipment (ballasts) than the 40-watt lamp. These lamps are being used more and
more as retrofits as well as in new construction.
Ballast Factor:
The ballast factor is a metric that defines the relative light output provided by a
ballast-lamp system with respect to the manufacturers rated light output for the
lamp specified in their catalog.
Filament Voltage:
The filament voltage applied to lamps by most electronic ballasts (2.1 to 2.4 volts) is
less than that applied by a standard CBM core-coil ballast (3.4 to 3.6 volts). Some
electronic ballasts remove all of the filament voltage during operation. This effect
will tend to reduce lamp life, but it will also reduce the power and result in a more
efficient system. The latest electronic ballast designs, labeled A to G, no longer
remove all of the filament power.
Lamp Current Crest Factor:
At 60 hertz the lamp current crest factor is greater for the 34-watt lamp than for the
40-watt lamp. There is virtually no difference in lamp current crest factor for the two
types of lamps with the electronic ballasts. Generally, the crest factor is greater for
the electronic ballast systems. However, lamp current crest factors range from 2.2 to
1.3. The higher lamp current crest factors, above the 1.7 ANSI recommended limit,
could contribute to reduced lamp life.
Open Circuit Voltage:
The measured open circuit voltage for the electronic ballasts is considerably greater
than that measured for the standard core-coil CBM ballast. The average and the
range of values measured for the electronic ballast. The higher open circuit voltage
will permit the lamps to start in a cooler ambient temperature. However, at higher
ambient temperatures the actual starting voltage will be considerably less than the
available open circuit voltage, especially if the filaments are suitably heated.
Open Circuit Voltage Crest Factor:
The range of values for the open circuit voltage crest factor for the electronic
ballasts. The average values are about the same as those measured for the core-coil
ballast. Some electronic ballasts have a value slightly above the recommended
maximum of 2.0. The higher crest factors increase the degradation of the filaments at
starting.
Flicker:
The range of flicker measured for the electronic ballast operating both types of
lamps. In general, the percent flicker is much lower when the lamps are operated at
high frequency (with electronic ballasts) than at 60 hertz (with a core-coil ballast). In
fact, some lamps operated at high frequency with an unmodulated waveform have
no flicker. A few electronic ballasts have fully modulated wave shapes at 60 hertz
which results in a percent flicker as high as that which occurs with the core-coil
ballast. The 34-watt lite white lamps have a lower percent flicker than the 40-watt
cool white lamps, because of the extra quantity of a yellow-emitting phosphor in the
mix. The red- and yellow-emitting phosphors generally have a larger persistence
than the blue emitting phosphors.
Light Output:
Lighting designers need to know the light output for each ballast-lamp system in
order to select the optimum lamp-ballast to meet their illumination needs. The range
of light output from the lamps operated with the different electronic ballasts is about
10 to 15 percent. The change in the light output for all types of ballast (core-coil and
electronic) operating the 34-watt F40 lamps is about 13 percent lower than the
output for ballasts operating the 40-watt cool white lamp.
System Efficacy:
The average efficacy is 79 to 80 lumens per watt for the electronic ballast systems
with either lamp. Some of the ballast designs achieves an efficacy of 83 to 84
lumens per watt. It is important to notice the very slight increase (~1 percent) in the
system efficacy for the 34-watt system, even though the 34-watt lamp is about 6
percent more efficacious than the 40-watt lamp. Thus, the system efficacy is about
the same for a ballast operating either lamp. In general, the electronic ballast systems
are 20 percent more efficient than the core-coil systems operating the same lamp.
QUESTIONS ?