What is a Ballast?
In Fluorescent Lighting systems a Lighting Ballast is a device which is designed to regulate the amount of electrical current required to start and illuminate a lamp. Maintaining sufficient voltage in a linear lamp is an extremely important aspect of a light fixture’s operation. Without the implementation of a ballast, the light fixture would be unable to control the amount of electrical current. Not controlling the electrical current can cause an electrical surge that may result in the destruction of the lamp.
Types of Ballasts
There are many different types of ballasts, which all differ in design and complexity. If you’re looking to replace a ballast or thinking about retrofitting a lighting fixture with a new ballast, make certain that the new ballast is compatible with the fixture and/or lamps. Carefully studying the Spec Sheets or contacting a lighting expert can save you from spending extra money or spare you from potential harm.
Electronic Ballast Types use solid state electronic circuitry in order to provide starting and operating electrical conditions that will power discharge lamps. Generally electronic ballasts are smaller and lighter than comparably rated magnetic versions. Electronic ballasts also usually run quieter than magnetic ones which generally produce a loud humming sound due to the vibration of the transformer lamination.
Fluorescent Lamp Ballast Types
Instant Start Ballasts do not preheat the electrodes. Instead they use a relatively high voltage to initiate the discharge arc in the lamp. It’s by far the most energy efficient variation, but it has a shorter overall lifespan as material is blasted from the cold surface of the electrodes each time the lamp arc discharge is initiated. Because of this fact, instant start ballasts are better suited for applications where the light fixtures are not frequently toggled on and off.
In Rapid Start Ballast types the ballast applies and heats the cathodes at the same time. This type of ballast is ideal for situations where lamp life and cycle life are major deciding factors. However it does use slightly more energy as the electrodes at each end of the lamp continue consuming heating power during the lamp’s operation.
Dimmable Ballast types are pretty similar to rapid start ballasts except they usually have a capacitor installed to give a power factor nearer to unity than a standard rapid start ballast. Dimmable ballasts work in tandem with a light dimmer in order to control the light level by varying the lamp current.
Program Start Ballast types are a more advanced version of the rapid start variation. This type of ballast is able to apply power to the lamp’s filaments first which in turn lets the cathodes preheat and apply voltage to the lamps to strike an arc. Once the fixture has been started, the voltage of filament is reduced so that it can increase the operating efficiency. Program start ballasts are preferred for applications with very frequent power cycling, such as bathrooms or other locations where you might want to install occupancy sensors.