Salient Features :-

• The ignitor, power factor capacitor and heavy choke are dispensed with, making the fitting    very light.
• The current drawn from the line is reduced by almost 60% of electrical ballasts.  Hence size of conductors required is reduced resulting in less capital investment
• HID lamps can start at lower voltages increasing utility.
• Power factor is increased to 0.95 and hence reduction of KVA requirement.
• Built in time delay for lamp restart with automatic adjustment for Metal Halide and Sodium Vapour lamps
• Less number of pulses per minute for restart and hence lamp life is increased.
• Completely serviceable unit.

• Suits any lamp from 5 - 18W. 
• Ballast loss is less than 2W
• Saves 25 - 30% in Direct Energy costs.
• Operates close to room temperature - less load on AC
• Increases life of lamps due to better output voltage stability
• Fully serviceable unit.

              Lighting specifies should consider six criteria when specifying high-frequency (20-60 kHz) electronic ballasts for linear fluorescent lamps: starting method, ballast factor, power factor and total harmonic distortion, lamp-ballast compatibility, inrush current, and ballast reliability The National Lighting Products information’s Program (NLPIP) prepared this Guide to Specifying High –Frequency
Electronics Ballasts including a sample specification from, to help lighting specifies understand and use manufacturer-supplied data to select appropriate high-frequency electronics ballasts –more detailed information ballasts, including manufacturer – Specific performance

Issues

Starting Method

  There are two major starting methods for electronic ballasts for linear fluorescent lamps:  rapid – start and instant –stain
Rapid-start ballasts Heat the electrodes of fluorescent lamps before applying the voltage necessary to start the lamps, causing a brief delay in starting Electrodes heating which usually continues even after starting results in a power loss if 3-4 watts.
            Instant –start ballasts Do not heat the lamp electrodes of during either starting or operation and so usually operate at lower power than comparable rapid-start ballasts. Instant start ballasts provide high initial starting voltage which will reduce lamp life relative to rapid start operation. This reduction in lamp life is greatest when lamps are turned on and off frequently, which sometime occurs in applications where occupancy sensors are used

Ballast Factor

          Ballast factor (BF)is the ratio of the light output of a lamp operated by given ballast to the light output of the same lamp when operated by reference ballast. For example lamps operated by a ballast with BF of 0.90 will provide 90% of their rated light output (Iumens) Different types of lamps operated by the same ballast may produce different BFs BFs between 0.85 and 1.0 are the most common. A lamp-ballast system with high BF which NLPIP defines as greater than 1.0 will produce high light output is that fewer lamps may be necessary in particular application Hoverer the high lamp current associated with high BF nay reduce lamp life and add to the energy required it operate the lamp that associated current may also accelerate lamp lumen depreciation which is a progressive decrease in light output.
Low BP (<0.85) systems produce low light output and can save energy because of their low system power compared to high BF systems. However low BF systems may reduce lamp life, due to reduced electrode temperatures.

Power Factor and Total Harmonic Distortion

              Power Factor (PF) is reduced as the ratio of active power (watts) to the apparent power (volt-amps) of the sinusoidal wave shapes. Low PFs result in the electrical distribution system and may Result in penalty fees from the electric utility company. The American National Standards Institute (ANSI) classifies ballasts with PF greater than 0.90 as “high power factor.”

            Total harmonic distortion (THD)  is a measure of the deviation from a sinusoidal waveform. High THD reduces power factor and may cause interference with the operation of electronic equipment, improper operation of power gird protective devices (fuses, circuit breakers and relays) interference with nearby communications circuits and overheating of motors transformers capacitors and neutral conductors.
ANSI requires that electronic ballasts have current THD less than 32 %. Most of the electronic ballasts on the US market have THDs of less than 20% Ballasts, With THD as low 5% are available but are usually mire expensive than other ballasts, and may have higher inrush current

Lamp-Ballast Compatibility

            Fluorescent lamps have specific ballasts requirements to ensure optimal operating characteristics and lamp life. Incompatible lamp-ballast systems may cause unreliable starting end darkening  and reduced life. ANSI has established standards for many of the compatibility factors these standards were summarized in the NLPIP publication

Guide to Fluorescent Lamp-Ballast Compatibility 

    The Certified Ballast Manufacturers Association (CBI) labels ballast That meet ANSI standards. Not all ballast manufactures participate in CBM and some ballast manufacturers choose to produce ballasts that do not comply with ANSI standards, A specified who chooses to use a ballast without a CBM label should also resolve the the question of who will warrant the lamp and ballast since lamp manufactures generally warrant their lamps only for operation with ballast that meet ANSI standards

Inrush current

            Inrush current is a momentary surge in current that can occur when an electrical device such as a motor or an electronic ballasts starts The duration of inrush current is very brief  typically less than 3 milliseconds High inrush current (>20A) can trip circuit breakers blow ruses or overload relays ANSI does not presently set limits for inrush current; however, some manufacturers incorporate devices to limit inrush current.
 
            Inrush current for an electronic ballast should meet the inrush specification for really circuit breakers, or fuses that may be included in the circuit, including those used in control devices such as
            Occupancy sensors and photo sensors. The specification for these other devices can be used to determine
The maximum current and duration for the ballast specification. The rated inrush current for the ballast must not exceed the rated inrush current for any other device in the circuit.
            Ballast Reliability Manufactures of electronic ballasts usually provide three-to five – year warranties for their products. Because ballast life depends on input voltage and ambient temperature, specifies should determine the acceptable ranges for input voltage and ambient temperature for the warranty to be valid, and ensure that conditions in the intended application will be within these ranges. Furthermore, NLPIP recommends that specifies determine whether the manufactures warranty includes labor costs for replacement of detective ballasts. The reliability of electronic ballasts can also depend on their ability to withstand voltage surges and electrical transients and to withstand operation for conditions outside of those for which the ballasts were designed. Some manufactures conduct special stress testing for their ballasts to determine their reliability in these conditions- NLPIP developed the list of questions below for specifies to use in discussions with manufacturers on ballast reliability.