Types of Ballasts
– Magnetic ballasts are commonly used in North America and Japan.
– Reactive ballasts operated at line frequency tend to be large and heavy.
– Electronic ballasts are smaller and lighter than magnetic ballasts.
– Electronic ballasts can be based on switched-mode power supply topology.
– Electronic ballasts can offer dimming capabilities and remote control.
Advantages of Electronic Ballasts
– Electronic ballasts eliminate the stroboscopic effect of flicker.
– Electronic ballasts have a higher system efficacy for low-pressure lamps.
– Electronic ballasts run cooler and are lighter than magnetic ballasts.
– Electronic ballasts can operate both high-pressure sodium and metal-halide lamps.
– Electronic ballasts offer the possibility of wireless mesh network control.
Fluorescent Lamp Ballasts
– Preheating systems use a combination filament-cathode and a switch to preheat the filaments.
– Resistive ballasts were used when the only available supply was DC.
– Instant start ballasts use a high voltage to initiate the discharge arc.
– Rapid start ballasts always heat the lamp electrodes using a heating transformer coil.
– Preheating systems are common in 200-240V countries.
Other Applications
– Ballasts were used in automobile ignition systems to regulate voltage.
– Ballasts are used in some consumer electronic equipment, such as television sets and record players.
– Sign ballasts are heavier duty due to cooler outdoor temperatures and are sized based on the total tube length used.
– European series choke ballasts are commonly used for fluorescent lamps.
– Inductors in line-frequency ballasts help strike the arc in the lamp and limit power losses, but can result in poor power factor.
Miscellaneous Concepts
– Dimmable ballast: Similar to rapid start ballast, incorporates a capacitor for power factor, can be used with a quadrac type light dimmer, requires a 10kΩ resistor for reliable firing at low light levels.
– Emergency ballast: Integrated battery for emergency egress lighting, alternative to egress lighting powered by a generator, requires regular testing, useful life of 10-12 years.
– Hybrid ballast: Magnetic core-and-coil transformer, electronic switch for electrode-heating circuit, operates at line power frequency, disconnects electrode-heating circuit after lamp starts.
– ANSI ballast factor: Used in North America to compare light output, compares lamp operated on a ballast to reference ballast, reference ballast operates lamp at nominal power rating, practical ballast factor must be considered in lighting design.
– Ballast triode: Used in early tube-based color TV sets, acts as a parallel shunt stabilizer for CRT acceleration voltage, keeps CRT deflection factor constant. Source: https://en.wikipedia.org/wiki/Ballast_(electrical)
An electrical ballast is a device placed in series with a load to limit the amount of current in an electrical circuit.
A familiar and widely used example is the inductive ballast used in fluorescent lamps to limit the current through the tube, which would otherwise rise to a destructive level due to the negative differential resistance of the tube's voltage-current characteristic.
Ballasts vary greatly in complexity. They may be as simple as a resistor, inductor, or capacitor (or a combination of these) wired in series with the lamp; or as complex as the electronic ballasts used in compact fluorescent lamps (CFLs).
