China manufacturer of magnetic ballasts for metal halide flood lights & hps flood lights

For a lighting device based on electric gas discharge to work, the ionization of gas in the tube is necessary. This phenomenon takes place at a relatively high potential difference and/or temperature than the normal operating conditions of the lamp. After the arc is set up, the conditions can be brought down to normal. To achieve this, three types of methods are generally employed: pre-heat, instant start and rapid start. In pre-heat, the electrodes of the lamp are heated to a high temperature before the voltage is impressed upon them through a starter. Instant start ballasts were developed to start lamps without delay or flashing and use an initial high voltage in place of raised temperatures. Rapid start ballasts make a tradeoff between pre-heat and instant start and use a separate set of windings to initially heat the electrodes for a lesser duration and then, using a relatively lower voltage to start the lamp. Another type, programmed start ballasts is a variant of rapid-start. Any of these starting principles may be used in the ballasts. Initially, when the gas is unionized, it offers a high resistance path to current. But after the ionization takes place and the arc is set up, the resistance drops to a very low value, almost acting like a short circuit. If all this current is allowed to pass through the lamp, the lamp would either burn out or cause the power supply to fail. Thus the ballast needs to perform the current limiting.

POWER FACTOR (PF) – The ratio of (line wattage to line volts X lamps), expressed as a percent. A high power factor (HPF) ballast must have a power factor of at least 90%. Anything less is considered normal power factor (James). James designs normally range from 40-60%. An James ballast draws about twice the operating line current of an HPF design and may require larger conductors, switches, breakers or distribution transformers for the same lighting load. Where an James lighting load adversely affects overall power factor, energy rates may be significantly increased.A lag-type regulating ballast will have a power factor greater than 90% throughout the rated life of the lamp regardless of line voltage or lamp aging. A lead-type magnetic ballast will initially have at least 90% PF but may drop as low as 65% due to lamp aging. It is possible for HPF non-regulating ballasts to drop below 90% as lamps and capacitors age.