What is a ballast in a light fixture?
ballast – A device required by electric-discharge light sources such as fluorescent or HID lamps to regulate voltage and current supplied to the lamp during start and throughout operation.
What is the life of a ballast?
According to the Certified Ballast Manufacturers Association, the average magnetic ballast lasts about 75,000 hours, or 12 to 15 years with normal use. The optimum economic life of a fluorescent lighting system with magnetic ballasts is usually about 15 years.
How do you tell if a light fixture has a ballast?
You can determine whether you have a compatible fixture in seconds. Simply turn the light on, then take a photo of the fixture using your smartphone or digital camera. If there are no dark bands on the resulting image, you have an electronic ballast that will work with direct drop-in LED tubes.
Why is it called ballast?
The term “ballast” comes from a nautical term for the stones used to stabilize a ship. Not all types of railway tracks use ballast.
How can you tell if a ballast is good?
One probe of the multimeter should touch the hot wire connections, while the other touches the neutral wire connections. If the ballast is good, an analog multimeter has a needle that will sweep to the right across the measuring scale. If the ballast is bad, then the needle won’t move.
What do ballast numbers mean?
The most common types are T12, T8, and T5. The T stands for tubular and the number indicates the diameter in 1/8 of an inch. Lamp diameter is determined by ballast type. A fixture with a T12 ballast must use a T12 bulb. A fixture with a T8 ballast must use a T8 bulb, etc.
What is the voltage rating of a fluorescent light ballast?
Newer fluorescent ballasts are usually rated for both 120 volts and 277 volts. Some are rated for only 120 volts, others for only 277 volts (used in commercial environments). CFLs for the home have a built-in ballast at the base of the bulb.
What do the numbers on the ballast of a light fixture mean?
The label on the ballast shows two important labels. Fluorescent tubes have two common shapes, straight and u-shaped. The most common types are T12, T8, and T5. The T stands for tubular and the number indicates the diameter in 1/8 of an inch. Lamp diameter is determined by ballast type. A fixture with a T12 ballast must use a T12 bulb.
What is the difference between rapid start and instant start ballasts?
Rapid start electronic ballasts heat the electrodes while applying the starting voltage (about 500 volts) to start the lamps quickly in about 0.5 to 1.0 seconds. Electrode heating continues while the lamps are on and consume a little more power (about 2 watts per lamp) than instant start ballasts.