Industrial 79W6091 001 Auto Transformer Module

The 79W6091-001 CW Auto Transformer is a 400W constant-wattage autotransformer ballast designed for 400W metal-halide lamps, specifically M59/H33 codes, used in HID luminaires. It accepts a line voltage range of 120/208/240/277 VAC and delivers stable lamp power across that span, maintaining consistent brightness and performance in diverse install conditions. The unit stands about 11.3 inches tall and weighs roughly 33 pounds, with a circuit type designated as CWA (Constant Wattage Auto). For safety and reliability, it includes an auto-reset thermal protector to prevent ignitor overheating in the event of a lamp failure. Manufactured under the Advance/Philips ballast lineage, this autotransformer module is built for metal-halide fixtures that require a 400W M59/H33 lamp and 120–277V supply, making it a drop-in solution for industrial and commercial HID lighting installations that demand dependable, watt-for-watt consistency.