Industrial LI501 H4 Lamp Ignitor

Philips Advance LI501-H4 Round HID ballast ignitor is a dedicated ignition module for high‑pressure sodium lighting, designed to start 150–400 W lamps in industrial ballast systems. It delivers the ignition pulse required to strike the arc, enabling reliable lamp startup in demanding environments such as warehouses and large parking structures. The unit runs on 120 VAC input and is specified for a maximum lamp distance of 2 ft in standard configurations. Its compact black housing measures about 2.16 inches in diameter and 4.75 inches long (roughly 2.16" dia, 4.75" length) with a depth near 1.25 inches, making it a drop‑in replacement for existing LI501‑H4 installations. This ignitor is part of the Advance Philips HID ballast family and is specified for 150 to 400 W high‑pressure sodium lamps, helping ensure consistent ignition performance across compatible fixtures.