What Is a Lighting Ballast?
In fluorescent and High-Intensity Discharge (HID) lighting systems, a light ballast regulates the current to the lamps while providing the correct voltage to start the lamps.
When the lamp initially starts up, the ballast briefly supplies high voltage to establish an arc between the lamp's two electrodes. Once the arc is established, the ballast quickly reduces the voltage and regulates the electric current, producing a steady light output. If there were no ballast in this type of lighting, a fluorescent lamp with a direct connection to a high-voltage power source would uncontrollably and rapidly increase its current draw. Within moments, the lamp would overheat and burn out.
Fluorescent and HID lamps are the two primary types of lamps that work with ballasts. There are five types of ballasts.
Types of Ballasts
Let’s learn more about each of the five types of ballasts to determine which one is right for your facility.
Electronic Ballasts
Today's modern lighting options (such as HID and fluorescent lamps) utilize electronic ballasts, which put out multiple frequencies of electricity without altering voltage input. This eliminates the flickering and buzzing associated with magnetic ballasts. Since electronic ballasts are much more energy efficient than magnetic ballasts, they're increasingly becoming the industry standard.
Compact Fluorescent (CFL) Ballasts
CFL ballasts are designed to start fluorescent lamps and keep them running. They come in both electronic and magnetic styles but electronic ballasts have the most up-to-date technology. CFLs are also offered in rapid- and instant-start models.
Dimming Ballasts
Dimmable ballasts are designed to include a full or partial range of light emissions. Electronic dimming ballasts are compatible with most fluorescent ballasts and can help reduce energy costs. Dimming ballasts are often placed in low-traffic areas and are compatible with a variety of accessories including occupancy sensors, dimming control switches, daylight sensors, and more.
HID Ballasts
HID ballasts come in two types of starting methods: probe-start ballast and pulse-start ballast. Pulse-start ballasts offer newer technology and greater energy efficiency than probe-start ballasts. HID ballasts are often found in car headlights.
Magnetic ballasts contain a copper wire that produces a magnetic field. This magnetic field traps much of the current, allowing for only the right amount of light to be emitted from the fluorescent tube. Magnetic ballasts are an older technology. Electronic ballasts are now the preference.
How Do Lighting Ballasts Work?
Ballasts have various types of starting technologies. Here's a look at a few and how they work.
Rapid-Start Ballasts
Rapid-start ballasts utilize a preheating method so the lamps turn on immediately when the light switch is turned on. Rapid-start ballasts prevent a lamp from flickering when turned on, so there is no strobe-light effect at start-up. Rapid-start ballasts are not very energy efficient, nor do they work reliably in cooler environments (50°F and below) such as in walk-in refrigerators or freezers.
Instant-Start Ballasts
Instant-start ballasts are the quickest lights to turn on. They start a lamp instantly by sending approximately 600 volts through the lamp to fire up the lamp's cathodes. They're designed to remain either on or off for extended periods of time compared with other ballasts and lamps. In fact, switching them on or off frequently will actually shorten the lamp's life. Instant-start ballasts work well in temperatures as low as 0°F while also being more energy efficient than rapid-start ballasts.
Programmed-Start Ballasts
Programmed-start ballasts commonly work in conjunction with motion or occupancy sensors. A programmed-start ballast works best with lighting where there are several on/off cycles throughout the day. They're ideal for placement in frequently used meeting rooms, conference spaces, or breakrooms, for example. Reliable at low temperatures, this type of ballast is energy efficient and maximizes the number of lamp-starting cycles.
Probe-Start Ballasts
Probe-start ballasts are an older-technology ballast for HID lamps that can actually reduce the performance of a lamp over time. After the switch is flipped, electrons within the HID lamp jump across the arc tube between two operating electrodes. Once the light starts, the starting probe electrode is removed from the circuit. Tungsten within the lamp sputters from the electrodes each time the lamp is turned on. This tungsten can eventually turn the inside of the arc tube black, which leads to a reduction in the performance of the lamp over time. Additionally, this start method takes longer for a lamp to warm up and reach its full brightness.
Pulse-Start Ballasts
Pulse-start ballasts utilize a high-voltage ignitor that works alongside the ballast. The ignitor sends a series of high-voltage pulses to start the lamp. More energy efficient than probe-start ballasts, pulse-start ballasts can actually prolong the life of a lamp by improving lumen performance. The electrodes in pulse-start ballasts heat up quickly which significantly reduces warmup time and tungsten spatter. Pulse-start ballasts continue to perform in temperatures as low as -40°F.
Having the right ballast in your lighting system will provide energy efficiency, money savings, and reliable visibility in your warehouse, conference rooms, and offices. Shop at Zoro for all of your lighting and business needs.
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Product Compliance and Suitability
The product statements contained in this guide are intended for general informational purposes only. Such product statements do not constitute a product recommendation or representation as to the appropriateness, accuracy, completeness, correctness, or currentness of the information provided. Information provided in this guide does not replace the use by you of any manufacturer instructions, technical product manual, or other professional resource or adviser available to you. Always read, understand, and follow all manufacturer instructions.