HMI®/MSR lamps are AC-operated discharge lamps in which the luminous arc burns in a dense vapor atmosphere comprising mercury and the halides of rare earths. The MSR in the part number indicates Medium Source Rare earth (MSR) elements, the number indicates the wattage, and the HR designates Hot Restrike.

HMI® lamps have a color temperature of 5600°K. Advantages of HMI®/MSR lamps over HID lamps is they warm up in 1-2 minutes and have an instant restrike ability. HMI® lamps can also be dimmed when operated from a ballast with dimming circuitry.

A properly designed ballast is required to operate a SeaArc® 2. SeaArc® 2 HMI®/MSR ballasts can be powered from either AC or DC voltage. It accepts a nominal input voltage of 120V or 240V, ranging from 110V to 300V. The ballast provides properly conditioned AC voltage/current required by the igniter circuit and lamp in the lighthead.

The HMI® ballast can even power DeepSea's proprietary TI/EB (Thallium Iodide/Electronic Ballast) lamp, a specially configured Thallium Iodide (TI) lamp. TI lamps produce an intense, monochromatic green light output (535 nm) which is close to the transmission "window" of seawater. The TI lamp offers maximum light penetration for long range monochromatic imaging applications such as submersible navigation and subsea surveying. TI lamps typically operate from HID magnetic ballasts. However, using a special igniter, this lamp gives users the flexibility to use one type of ballast to power an HMI® or a TI lamp. You can freely swap lightheads with no modification to the ballast. DeepSea offers a dual ballast housing, so that users can operate a TI/EB and HMI from the same housing.

There are options available in the types of reflectors, depth rating, types of material, and types of ballasts. Please call DSP&L for assistance in determining the best combination of options to meet your requirements.