What is an autotransformer ballast?
High-reactance autotransformer (HX-HPF): These ballasts are similar in performance to reactor ballasts (discussed below), but their additional coils allow them to start the lamp from supply voltages that are lower than those necessary to start the lamps.
What does a ballast capacitor do?
Capacitors, available in both oil-filled and dry-film technologies, are used with some HID ballasts in order to improve their power factor, light output, and even efficiency by regulating the inrush current that occurs when the light is initially started.
What is a CWA circuit?
CWA circuits have been modified for HPS lamps, but use more materials and result in higher losses. This is also an issue for metal halide lamps that rise in voltage with aging. The result is lamp-to-lamp power variation that shows up as lamp-to-lamp color variation.
Which ballast is used in sodium lamp crest factor?
Normally to obtain HPF in electronic ballast for high pressure sodium lamps a power factor preregulator (PFP) is used between the mains and the electronic ballast. The main idea in this work is to present a simple and cheap electronic ballast with HPF for HPS lamps.
What are the two functions of ballast?
Functions of Ballast
- To provide firm and level bed for the sleepers to rest on.
- To allow for maintaining correct track level without disturbing the rail road bed.
- To drain off the water quickly and to keep the sleepers in dry conditions.
- To discourage the growth of vegetation.
What is a CWA ballast?
Constant-wattage autotransformer (CWA): Also known as lead style ballasts, CWA ballasts are the most common ballasts used on 175 W or higher MH lamps. This type of ballast has a different design than the reactor and high-reactance autotransformer (HX-HPF) ballasts.
Which of the following is used for starting high intensity metal halide and sodium Vapour lamp?
Igniters are used for Metal-Halide lamps because they operate at a pressure between 4 and 20 atmospheres so require special fixtures to operate safely, as well as an electrical ballast and a special igniter to ensure a reliable and instantaneous lamp ignition.
How does a ballast transformer work?
In its simplest form, a ballast uses magnetic energy that erupts into the lamp when it is turned on, stimulating the electrodes to make a current and the lamp glows.
What is the difference between a ballast and a transformer?
A transformer changes the amperage and / or voltage. It literally “Transforms” electrical energy. A ballast is like a capacitor. Think of a ballast as a short-term battery.
What are the different types of ballasts?
And there are two types of ballasts in each family: magnetic and electronic. Magnetic ballasts are the older ballast technology. For the fluorescent family, both T12 linear fluorescents and two-pin CFLs use magnetic ballasts. For HIDs, some metal halides and HPS lamps use magnetic ballasts.
Which variation of CWA ballast is used with metal halide lamps?
Constant-wattage autotransformer (CWA): Also known as lead style ballasts, CWA ballasts are the most common ballasts used on 175 W or higher MH lamps.
What type of autotransformer ballast should I use?
The constant wattage autotransformer HID ballast type should be used where a stabilized light output is required. CWA is an HID ballast type that comes in a fairly small economical size, yet still provides a reasonable degree of regulation.
What’s the CWA ballast?
What’s the CWA ballast? The constant wattage autotransformer HID ballast type should be used where a stabilized light output is required. CWA is an HID ballast type that comes in a fairly small economical size, yet still provides a reasonable degree of regulation.
Are dielectric materials in magnetic ballasts toxic?
Prior to 1980, the dielectric fluid and potting material in magnetic ballasts contained polychlorinated biphenyls (PCBs), a highly regulated, highly toxic carcinogen. Congress banned the manufacture of PCBs in 1977 and banned their use in 1979 in all but totally enclosed equipment.