Magnetic ballast :
An Electronic Ballast is a device which came into existence by a replacement to Electrical Ballast.
Hybrid ballasts .
Hybrid ballast uses a magnetic core and coil transformers and an electronic switch for the electrode heating circuit. Like magnetic ballast, this also operates at 50Hz but difference is it disconnects the electrode heating circuit after it starts the lamp. Thus this system consumes lesser power than magnetic ballast, are more costly too.
Electronic ballasts.
With the advances in solid state technology, core and coil transformers were replaced, with electronic components that operate lamps at higher frequency in the range of 20 to 60 KHZ.
The electronic ballast has power loss almost half the magnetic ballasts
High frequency electronic ballasts for fluorescent lighting systems also called solid state ballasts are promoted as providing significant energy savings over magnetic ballasts.
The acceptability of this ballast has grown rapidly in recent years. The National Appliance Energy Conservation Act in 1987 influenced elimination of High Loss magnetic ballast and hence it prompted more use of Electronic Ballast.
Lamp efficacy also increases by approx. 10 to 15% as compared to operation at 50Hz. And selection of frequency is available. Initial cost of this ballast is higher than earlier ballasts; they reduce watt loss by 10 to 15 w on average compared to magnetic ballasts. Further they are almost noise less and lighter in weight too. The flicker is virtually eliminated.
The versions available could be of instant start, rapid start, or program start.
In Instant start mode, lamps glow without heating cathodes by using a high voltage. It is most energy efficient type but gives least no. of starts from a lamp as emissive oxides are blasted from the cold cathode surfaces each time lamp is started.
In rapid start mode, applies voltages to the cathodes and heats them up simultaneously. Provides superior lamp life and more cycle life as well. But uses slightly more energy.
In programmed start mode, it’s an advance version of rapid start. Applies heat with voltage to filaments first, than after a short delay to allow pre heat to cathodes, applies voltage to lamp to strike an arc. The best life and most starts from lamp results. Best suited mode for very frequent power cycling, such as visual examination rooms, rest rooms with a motion detectors switches.
The Electronic ballasts are now available for T5 4 ft lamps. In no way they are intended to replace T8, T10, and T12 lamp ballasts because it requires different luminaries.
T8, a 4ft & 8 ft tube lamps Ballast are now used with electronic ballast most however with magnetic ballast usage option.
Similarly T10 & T12 - 4ft & 8 ft lamps do use either of the ballasts. However it should be noted that major manufacturers of 34 watt – T12 lamps specify that such lamps should not be used with dimming ballast.
And by using it hidden benefits are:
• The Electronic Ballast offers near unity power factor as a basic feature.
• No excess heating so no extra loss of Power.
• Wherever Air Conditioners are installed, to maintain required temperature of Air conditioned cabin / office or plant or specific area, the cooling machine has to run more to pump in more cool air and thus additional loss of power.
The effective power conservation is possible in textile industry running 24 x 7 round the year. Rs. 1/- or more per lamp is possible saving and the present designs offered are such that units can be repaired and reused. Thus tremendous power saving directly as well indirectly is possible. Reduction in Load demand is yet another achievement.
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