SECTION 1 – SAFETY PRECAUTIONS - READ BEFORE USING

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1-1. Symbol Usage

Means Warning! Watch Out! There are possible hazards with this procedure! The possible hazards are shown in the adjoining symbols.

Y Marks a special safety message.

This group of symbols means Warning! Watch Out! possible

ELECTRIC SHOCK, MOVING PARTS, and HOT PARTS hazards.

 

. Means “Note”; not safety related.

Consult symbols and related instructions below for necessary actions

to avoid the hazards.

1-2. Arc Welding Hazards

YThe symbols shown below are used throughout this manual to call attention to and identify possible hazards. When you see the symbol, watch out, and follow the related instructions to avoid the hazard. The safety information given below is only a summary of the more complete safety information found in the Safety Standards listed in Section 1-5. Read and follow all Safety Standards.

YOnly qualified persons should install, operate, maintain, and repair this unit.

YDuring operation, keep everybody, especially children, away.

ELECTRIC SHOCK can kill.

Touching live electrical parts can cause fatal shocks or severe burns. The electrode and work circuit is electrically live whenever the output is on. The input power circuit and machine internal circuits are also

live when power is on. In semiautomatic or automatic wire welding, the wire, wire reel, drive roll housing, and all metal parts touching the welding wire are electrically live. Incorrectly installed or improperly grounded equipment is a hazard.

DDo not touch live electrical parts.

DWear dry, hole-free insulating gloves and body protection.

DInsulate yourself from work and ground using dry insulating mats or covers big enough to prevent any physical contact with the work or ground.

DDo not use AC output in damp areas, if movement is confined, or if there is a danger of falling.

DUse AC output ONLY if required for the welding process.

DIf AC output is required, use remote output control if present on unit.

DDisconnect input power or stop engine before installing or servicing this equipment. Lockout/tagout input power according to OSHA 29 CFR 1910.147 (see Safety Standards).

DProperly install and ground this equipment according to its Owner’s Manual and national, state, and local codes.

DAlways verify the supply ground – check and be sure that input power cord ground wire is properly connected to ground terminal in disconnect box or that cord plug is connected to a properly grounded receptacle outlet.

DWhen making input connections, attach proper grounding conduc- tor first – double-check connections.

DFrequently inspect input power cord for damage or bare wiring – replace cord immediately if damaged – bare wiring can kill.

DTurn off all equipment when not in use.

DDo not use worn, damaged, undersized, or poorly spliced cables.

DDo not drape cables over your body.

DIf earth grounding of the workpiece is required, ground it directly with a separate cable.

DDo not touch electrode if you are in contact with the work, ground, or another electrode from a different machine.

DUse only well-maintained equipment. Repair or replace damaged parts at once. Maintain unit according to manual.

DWear a safety harness if working above floor level.

DKeep all panels and covers securely in place.

DClamp work cable with good metal-to-metal contact to workpiece or worktable as near the weld as practical.

DInsulate work clamp when not connected to workpiece to prevent contact with any metal object.

DDo not connect more than one electrode or work cable to any single weld output terminal.

SIGNIFICANT DC VOLTAGE exists after stopping engine on inverters.

DStop engine on inverter and discharge input capacitors according to instructions in Maintenance Section before touching any parts.

ARC RAYS can burn eyes and skin.

Arc rays from the welding process produce intense visible and invisible (ultraviolet and infrared) rays that can burn eyes and skin. Sparks fly off from the weld.

DWear a welding helmet fitted with a proper shade of filter to protect your face and eyes from arc rays and sparks when welding or watching (see ANSI Z49.1 and Z87.1 listed in Safety Standards).

DWear approved safety glasses with side shields under your helmet.

DUse protective screens or barriers to protect others from flash and glare; warn others not to watch the arc.

DWear protective clothing made from durable, flame-resistant mate- rial (wool and leather) and foot protection.

FUMES AND GASES can be hazardous.

Welding produces fumes and gases. Breathing these fumes and gases can be hazardous to your health.

DKeep your head out of the fumes. Do not breathe the fumes.

DIf inside, ventilate the area and/or use exhaust at the arc to remove welding fumes and gases.

DIf ventilation is poor, use an approved air-supplied respirator.

DRead the Material Safety Data Sheets (MSDSs) and the manufacturer’s instructions for metals, consumables, coatings, cleaners, and degreasers.

DWork in a confined space only if it is well ventilated, or while wearing an air-supplied respirator. Always have a trained watch- person nearby. Welding fumes and gases can displace air and lower the oxygen level causing injury or death. Be sure the breath- ing air is safe.

DDo not weld in locations near degreasing, cleaning, or spraying op- erations. The heat and rays of the arc can react with vapors to form highly toxic and irritating gases.

DDo not weld on coated metals, such as galvanized, lead, or cadmium plated steel, unless the coating is removed from the weld area, the area is well ventilated, and if necessary, while wearing an air-supplied respirator. The coatings and any metals containing these elements can give off toxic fumes if welded.

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Miller Electric 251 NT manual Symbol Usage, Arc Welding Hazards, Electric Shock can kill, ARC Rays can burn eyes and skin

251 NT specifications

The Miller Electric 251 NT is a highly regarded multi-process welding machine known for its versatility and advanced features, making it an ideal choice for professionals in various industries. With its robust construction and user-friendly interface, the 251 NT provides an efficient solution for MIG, TIG, and Stick welding applications.

One of the main features of the Miller Electric 251 NT is its impressive output range, which allows for welding on a variety of materials and thicknesses. It delivers up to 250 amps of power, enabling users to tackle both thin and thick metals with ease. Additionally, the machine is equipped with an Auto-Set feature, which automatically adjusts the welding settings according to the material thickness and type. This eliminates the guesswork, significantly enhancing productivity and reducing setup time.

Another noteworthy aspect of the Miller Electric 251 NT is its inverter technology. This advanced technology provides a compact, lightweight design without compromising performance. Inverter technology allows for greater energy efficiency, resulting in reduced operational costs over time. The 251 NT also features a Duty Cycle of 60% at 250 amps, which means it can handle demanding tasks while maintaining optimal performance.

The Miller Electric 251 NT is designed with user convenience in mind. The intuitive digital display offers clear visibility of the settings, allowing welders to make quick adjustments. Furthermore, the machine includes a built-in memory function to store frequently used parameters, enhancing workflow efficiency.

Safety is a key component of the 251 NT's design. It comes equipped with various safety features, including overload protection and a thermal overload warning system. These features ensure that the machine operates within safe limits, minimizing the risk of damage and ensuring longevity.

In terms of portability, the Miller Electric 251 NT's lightweight design and integrated handle make it easy to transport between job sites. The durable housing protects the internal components, making it suitable for rigorous use in demanding environments.

Overall, the Miller Electric 251 NT offers a combination of power, flexibility, and ease of use, making it a top choice for welders looking to enhance their capabilities across multiple welding processes. Whether in a professional shop or on a construction site, the 251 NT stands out as a reliable and efficient welding solution.