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   Ballast FAQ          

1) Why do fluorescent lamps need ballast?

Fluorescent lamps are high pressure gaseous lamps. An arc has to be created between the 2 electrodes which are paced distantly. It needs substantial high voltage to ignite and create an arc and later, lamp being negative impedance current control after ignition is must else the infinite current can flow and result in damage of lamp. These 2 basic functions are done by ballast. It provides sufficient ignition voltage initially and later controls the lamp current to the value as per the lamp.

2) What are the differences between magnetic and electronic ballast?

Magnetic ballast has been around since the beginning of fluorescent lighting. They employ copper coils and transformers to run a lamp. Magnetic choke (ballast) cost less, but weigh more and, more importantly, are less efficient than modern electronic ballast. Electronic ballast use 25% less energy than magnetic, do not hum or flicker when starting, and have a lower THD. Electronic ballast can operate from 90V input to 300V input whereas magnetic ballast works from 180V to 250V. With increased voltage lamp power increases and reduces lamp life. The federal government has mandated magnetic ballast be replaced with electronic ballast over the next several years.

3) Do fluorescent lights flicker with electronic ballast?

Because electronic ballast operates at higher frequencies than magnetic ballast, the amount of light flicker is minimized. This reduces eye fatigue in people.

4) Does the ballast always need to be grounded?

Yes, the ballast case and fixture must always be grounded. This helps assure safety, proper lamp starting, and acceptable performance of the lamp ballast system.

5) What are the different lamp types your ballast will run?

Below is the list of the most common types of lamps taken as general sampling. Compact fluorescent lamps come in the 7W, 9W, 11W, 10W, 13W, 18W, 26W, 32W, 36W, 40W, 42W and 55W options. Our compact fluorescent ballast will run these lamps. T8 lamps are made in 18W, 36W, 25W, 32W and 40W types. T5 lamps come in 14W, 21W, 24W, 28W, 35W, 39W, 49W and 54 W types. Above list is not exhaustive and we recommend you talk to your sales agent about specific lamp types.

6) Can I run one lamp with two-lamp ballast?

In most applications yes, but it is always advisable to check with our technicians first.

7) What is ballast factor and why is that important?

Ballast Factor (BF) is a measurement that compares the ratio of light output of a lamp or lamps operated by commercial ballast to the light output of the same lamp or lamps operated by reference ballast. The higher the BF is, the higher the wattage running through the ballast. Some applications need a lower BF to conserve energy and reduce light output, while others prefer a higher BF to increase light output. However, a higher BF does decrease the life of the lamp.

8) What is THD?

THD stands for Total Harmonic Distortion. Normally, wave shape of the supply voltage provided by utility is sine in nature. The distortion generated by the electronic or electrical ckt. in multiples of fundamental frequency is THD. Higher percentage of Current THD calls for bigger size of conductors to handle these harmonic current, higher loads on mains distribution transformers, increased losses and many other disadvantages. Current harmonics of odd levels are important and mainly the third harmonic. IEC standard IEC61000-3-2 deals with the limits of harmonics for lighting equipment with maximum ATHD of 33%. All Intelux ballasts are rated for less than 30% or 10% depending on the ballast models.

9) What is the difference between Instant start and Rapid start ballast?

Instant Start (IS) ballast requires a larger amount of energy to start the lamp than Rapid Start (RS). This can reduce the lamp life by up to 25% if you turn the light on and off quite a often. However, IS ballast does use less energy than the RS ballast, passing on energy savings to the customer. RS ballast preheat cathodes before turning on the lamp, and more energy is used to keep the cathodes constantly heated. With RS, one gets more lamp life, but less efficiency. IS ballast are more popular because they are less expensive and have fewer wires for installation. IS ballast are popular with T8 lamps.

10) What is Power Factor?

Power Factor (PF) is the measurement of how effectively ballast converts the voltage and current supplied by the power source into watts of usable power delivered to the ballast and lamps. Perfect power utilization would result in a power factor of one.


11) What is Crest Factor?

Crest Factor is the ratio of Peak voltage or current to RMS voltage or current respectively. Higher the crest factor higher the peaks, hence higher the losses. Lamp current crest factor relates to the lamp life with the ballast. Higher the lamp current crest factor, means reduced lamp life. Normally a lamp crest factor of 1.7 maximum is allowed.


12) What is the difference between Parallel and Series Wiring?

Ballast with parallel circuits operate each lamp individually. If one lamp goes out, the companion lamps stay lit. Series circuits include every lamp in the same electrical circuit "loop." If one lamp stops working, every lamp will cease functioning.

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