Run Up of the Lamp

After the lamp receives the strike from the starter and the arc is established, the ballast uses its -360 volt output in order to provide the run up power needed in order to keep the lamp on. The lamp rapidly increases in intensity from a dim glow to a very high-intensity, bright light called a steady state. Within 2 seconds of the arc being established in the bulb, 70% of steady state is complete. 100% of the steady state is completed within 30 seconds. A 75-watt power level is necessary in order to bring the lamp to a steady state in such a short period of time. The 75-watt power level allows the lamp to meet the SAE light vs. time specification.