An electrical ballast s a device that provides the correct amount of voltage and current to the correct components in an electric circuit.
In simple terms, it is a resistor or diode with a specific number of ohms or volts. These devices protect against surges like an arc discharge, extend bulb life, prevent overheating, increase efficiency and save energy by regulating power in an electronic system. They are most commonly used to operate gas discharge lamps, like an HID lamp or a fluorescent lamp. You can determine how much light a lamp operated on a given ballast will emit based on the ballast factor (also known as the power factor). The lamp's ballast factor is a number that is usually between 0.70 and 1.2. The ballast factor is calculated based on the lumen output of a lamp ballast, as well as the output of a reference ballast using the same lamp. A low ballast factor (under 1) means the lamp produces less light than the reference and there are greater ballast losses, and a high ballast factor (over 1) means the lamp produces more light than the lamps operated by the reference and there are fewer ballast losses. There are several types of ballasts, including the below.
Dimmable ballast.
Magnetic ballast.
Switch start ballast.
Inductive ballast.
Reference ballast.
A reference ballast is a special type of ballast used to test lamps and ballasts. The ballast starts using one of three types of technologies:
Rapid start ballast (provides a continuous current and allows the mercury in a fluorescent lamp to conduct electricity).
Instant start ballast (this is different from a rapid start ballast).
Programmed start ballast.
When electricity passes through something with resistance (ie: ballast) some of it is lost in the form of heat. The more resistance there is, the more heat (energy) will be dissipated in that object; this creates what we know as 'heat loss'. As electricity passes through a ballast, the resistance in that device causes what is known as 'inrush current'. This is why ballasts need to be designed specifically for the type of light bulb or the lamp type they are powering; if a ballast isn't made to compensate for this surge, it can lead to permanent damage and shortened lifespan. For example: If you try and use a 20W halogen lamp with a 10W ballast, it will cause significant damage, so much so that many cheaper designs will blow up, meaning an expensive replacement.
Unfortunately, when an electrical ballast goes bad it can cause all sorts of symptoms. These symptoms will vary depending on the kind of lamp and ballast you are using; however, there are some common symptoms to look for:
Flickering light (on/off flicker).
Bulb produces unusual or little light (may appear dimmed and give off less light).
Bulbs burn out very quickly (i.e.: within days or weeks).
A "bad" ballast usually results in any one - or a combination - of these symptoms. If you're experiencing any of these symptoms then it's probably time to replace your old ballast with a new one! The good news is that this is usually pretty easy to do and inexpensive.
There are a wide variety of electrical ballasts. There are many different shapes, sizes, and styles of ballasts on the market; different kinds for different kinds of lights. Keep in mind that not every ballast will work with every lamp type, so it's very important you purchase the correct one for your application. Some examples include: High-intensity discharge (HID) ballasts and high-intensity discharge (HID) lamps, low-pressure sodium (LPS), compact fluorescent lamps (CFL), and metal halide lamps (MH). Each of them is used in different places - for example, HID lamps are used in movie theatres and football stadiums.
A fluorescent lamp ballast is an electrical device that provides the correct amount of voltage to the proper components in an electronic circuit. The ballast will transform line voltage. The line voltage will be changed to voltage to allow for lamp operation. Additionally, the ballast will help regulate current and voltage usage by your lighting fixture. Current limiting features help limit the amount of electric current used, extends its life, and ensures it is as energy efficient as possible. At its heart, all adjustable light output magnetic ballasts are made up of two coils - one primary coil (usually called the "running" coil) and one secondary coil (the "starting" coil).
One common mistake is failing to properly identify an old or new ballast. If you are unsure whether the ballast is an electronic or magnetic ballast, simply remove and flip it over. An electronic ballast will have two wires exiting from each side of the lamp holder; the magnetic counterparts will only have one wire on one side of the lamp holder. Another common mistake occurs when installing a ballast for a different wattage than is required by the light fixture's bulb(s). For example, You can't use a 150W ballast with a 100W bulb. Lastly, failure to use overcurrent protection (ie: fuses) in conjunction with all electronic magnetic ballasts can damage your lights and void your warranty, so be very careful when working with higher value lighting systems in particular. The most important thing to remember when replacing any component in your electrical lighting system is to identify what you have first. This is the only way to ensure that your replacement part will work properly, safely, and efficiently with all of your other electrical fixtures.
There are many reasons you may have a bad ballast. The first thing to remember is that all ballasts will eventually fail, it's just a matter of time. There are several factors that can lead to this failure including:
Voltage variations (moving from high voltage to low voltage or vice versa - low to high voltage) and voltage drop within the facility due to faulty wiring or an interruption in power supply.
Vibration/shocks from malfunctioning equipment being operated nearby.
Damage during installation.
When your ballast fails (i.e.: won't start the light), one of two things will happen: Your lamps will produce extremely low output (in some cases none at all) or they will flicker on and off intermittently. Both situations indicate that your ballast has failed and should be replaced immediately to avoid additional damage to your lighting system.
A flickering or pulsating light is usually an indication that one or more lamps are not starting properly. This can result from a number of causes, such as:
The fixture has been installed with the wrong wattage lamps. If you're using CFL lamps in a metal halide fixture, for instance, they may fail to ignite because of insufficient input voltage. As a result, dimming and flickering may occur as the lamp repeatedly tries and fails to ignite.
A dirty lens will scatter the light output from fluorescent lighting preventing them from igniting properly. Cleaning both ends of each fluorescent tube (where it enters the fixture and where it exits) with a wet-dry vacuum cleaner can resolve this issue.
Many ballasts have started to include manual on/off switches which, when activated, force lamps to start without requiring the ballast to provide power. If your switch is activated but your lamps are still flickering or not turning on hold down the switch for 15 seconds or more to discharge any residual voltage in the system.
A fluorescent lamp should never be operated without its lens cover in place because doing so may damage the fixture's electrical components if current leakage occurs through the gap between lamp units/lens covers. Turn off all of your lights before installing or replacing lenses, otherwise you could electrocute yourself and/or cause damage to your equipment. Best to use an electrician.Below are the different types you can buy.
These are the most common type of ballast and use magnetic induction to create an electrical current in the coil of the fixture. The magnetic field produced ensures that only the right amount of voltage gets to the lamp. They hold an efficiency rating of around 85% which is lower than an electronic ballast but they don't require any external power or special capacitors, making them slightly more efficient for very small light sources such as those found on holiday decorations.
This high-efficiency lighting system uses transistors to provide a current flowing directly through the coils of a fluorescent fixture which incurs a higher cost but delivers more lumens per watt and contributes largely to energy conservation efforts across the country. Although their initial cost may be slightly higher, these units quickly pay for themselves by lasting roughly 10 times longer than magnetic ballasts. An electronic ballast also operates at a higher temperature which results in less power loss through heat over time and lower emissions of the harmful UV-A rays which can cause cancer in humans. Electric ballasts supply power to the lamp at a high frequency, usually 20,000 Hz or more. These higher frequencies help eliminate the flickering effect. Additionally, the power supplied is at a much higher frequency than a magnetic ballast, and high frequency also reduces the likelihood of buzzing sounds. However, if your electronic ballast starts leaking oil, it's time to replace it.
This type of lighting system is primarily used in smaller, short-term applications such as holiday decorations, party lights, and costumes. Although they typically have a shorter lifespan than other ballast types, these units are very inexpensive and can be found for under five dollars each. In most cases, capacitor systems will burn out immediately if there is a problem with your circuit breaker or wiring - try switching to another outlet before discarding this type of unit.
If you are looking to replace a ballast for any existing fixture, be sure to measure it before purchasing a replacement. Dimensions of many electronic ballasts (as well as of a magnetic one, if you prefer a magnetic ballast) are commonly found on the product label along with wattage suggestions based on the size of room that your light fixtures are intended for. If you're unable to find this information on your unit however, there are some easy steps that will allow you to determine lamp wattage requirements which are as follows:
Determine the number of lamps installed by counting how many separate tubes/bulbs/lenses appear in the lighting system.
Subtract one from this total because most "starter" fittings actually contain two bulbs - one on top of the other - and we only need to count the top one.
Determine lumen (light) output by multiplying width, height and length of your room for square footage or by determining the surface area of your walls using a tape measure if you don't know how big it is.
Add up wattage across all lamps installed on the system and divide this number by either 800 (for electronic lighting ballast systems) or 120 (for magnetic ones). This will provide you with recommended lamp wattage.
Ballasts are generally available in ¼, ½ or 1-watt increments so choose accordingly. If none of these options matches within 10% of your final measurement, rounds down to obtain more reliable performance from your lighting system.
Here's how to change or replace a light ballast.
Most standard magnetic ballasts will require a warm up period of roughly 10 minutes before their full wattage is available to your lighting system. Some fixtures may take longer or shorter depending on size and age; we recommend checking the manual that came with your equipment for more specific information if you can't find it.
Magnetic systems may hum, flicker and/or cause lights to dim during use and these symptoms should dissipate over time as they run at cooler temperatures than electronic ones - however, if you notice that this happens immediately after turning your light fixture(s) on then it's possible that there is something wrong such as a worn out (dying ) tube or failing capacitor which must be replaced.
If you are experiencing issues with your magnetic light ballast, be sure to turn off the system at its power source, not just the switch, before attempting any repairs, just to be safe around electricity. Once the ballast is disconnected from power, simply remove the screws that keep it connected to your light fixture or adapter and replace them with a matching wattage alternative.These systems may initially buzz when activated, though there should be limited to no buzzing once they start working. However, this type of ballast is not a dimmable ballast and will not dim during proper operation - if they do dim then there is likely something wrong which must be addressed. Electronic units typically only change in intensity by roughly 10% so pay close attention to this area when making changes. All electronic systems should be turned off before attempting any repair work or changing components. Once you've located the unit inside of your lighting fixture, disconnect power at the breaker or fuse box before removing it for service. An electronic ballast usually consists of capacitors and/or coils which can become burnt out if they are not properly maintained. If your system emits a clicking sound during operation, this usually indicates that the capacitor is failing so be sure to check its resistance with an ohmmeter to check the ohm setting and determine whether or not it needs to be replaced.
Determine the number of lamps installed by counting how many separate fluorescent tubes/bulbs/lenses appear in the lighting system.
Subtract one from this total because most "starter" fittings actually contain two bulbs - one on top of the other - and we only need to count the top one.
Determine lumen (light) output by multiplying width, height and length of your room in feet then divide the total by 10.4 to obtain - for example a 12ft x 18ft room would be 144 ft2 (12 x 18 = 216) which multiplied by 10.4 gives us 2232 lumens required.
4ft wide fluorescent lamps are usually 30w, T8 twist/pin types are 38w and T12 are 54 watts each so you can safely determine that four of these will provide enough brightness without overtaxing your system.
Look up ballast wattage on the manufacturer's website or use a calculator which provides ballast ratings in both magnetic and electronic form. If you choose to replace it with an electronic ballast, pick one that is compatible with your existing system and wattage recommendations to avoid issues. Electronic ballasts usually consist of capacitors and/or coils which can become burnt out if they are not properly maintained. If your system emits a clicking sound during operation, this usually indicates that the capacitor is failing so be sure to check its resistance with an ohmmeter to determine whether or not it needs to be replaced.