Bobcat 250 NT - Miller

1 Bobcat 250 NTProcessesDescription Non-Critical TIG (GTAW)WeldingStick (SMAW) WeldingMIG (GMAW) WeldingFlux Cored (FCAW) WeldingEngine Driven Welding GeneratorOM-4403200 291 LApril 2004 Visit our website Electric manufactures a full lineof welders and welding related information on other quality Millerproducts, contact your local Miller distributor to receive the latest fullline catalog or individual catalog sheets. To locate your nearestdistributor or service agency call 1-800-4-A- Miller , or visit us on the you and congratulations on choosing Miller . Now you can getthe job done and get it done right. We know you don t have time to doit any other s why when Niels Miller first started building arc welders in 1929,he made sure his products offered long-lasting value and superiorquality.

2 Like you, his customers couldn t afford anything less. Millerproducts had to be more than the best they could be. They had to be thebest you could , the people that build and sell Miller products continue thetradition. They re just as committed to providing equipment and servicethat meets the high standards of quality and value established in Owner s Manual is designed to help you get the most out of yourMiller products. Please take time to read the Safety precautions. Theywill help you protect yourself against potential hazards on the ve made installation and operation quickand easy. With Miller you can count on yearsof reliable service with proper if for some reason the unit needs repair,there s a Troubleshooting section that willhelp you figure out what the problem is.

3 Theparts list will then help you to decide theexact part you may need to fix the and service information for yourparticular model are also is the first weldingequipment manufacturer inthe to be registered tothe ISO 9001:2000 QualitySystem as hard as you do every power source fromMiller is backed by the mosthassle-free warranty in Miller to YouMil_Thank 7/03 TABLE OF CONTENTSSECTION 1 SAFETY PRECAUTIONS READ BEFORE USING1 .. Usage1 .. 1-2. Arc Welding Hazards1 .. Hazards2 .. Air Hazards3 .. Symbols For Installation, Operation, And Maintenance3 .. Proposition 65 Warnings4 .. Safety Standards4 .. Information4 .. SECTION 2 CONSIGNES DE S CURIT LIRE AVANT UTILISATION5 .. des symboles5 .. relatifs au soudage l arc5 .. existant en relation avec le moteur6.

4 Li s l air comprim 7 .. suppl mentaires en relation avec l installation, le fonctionnement et la maintenance7 .. normes de s curit 8 .. sur les champs lectromagn tiques8 .. SECTION 3 DEFINITIONS9 .. SECTION 4 SPECIFICATIONS9 .. 4-1. Weld, Power, and Engine Specifications9 .. , Weights, and Operating Angles10 .. Power Curve10 .. Consumption (Onan-Powered Units)11 .. Consumption (Kohler-Powered Units)11 .. 4-6. Volt-Ampere Curves12 .. 4-7. Duty Cycle13 .. SECTION 5 INSTALLATION14 .. Welding Generator14 .. 5-2. Engine Prestart Checks (Onan-Powered Units)15 .. Prestart Checks (Kohler-Powered Units)16 .. The Dry Charge Battery (If Applicable)17 .. the Battery18 .. Exhaust Pipe18 .. to Weld Output Terminals19 .. Weld Cable Sizes*19.

5 SECTION 6 OPERATING THE WELDING GENERATOR20 .. Panel Controls20 .. 6-2. Typical Stick Welding Connections And Control Settings21 .. 6-3. Typical MIG Welding Connections And Settings22 .. 6-4. Typical MIG Connections And Settings Using Weld Control And Spoolgun24 .. SECTION 7 OPERATING AUXILIARY EQUIPMENT25 .. Receptacles25 .. Generator Power Receptacles26 .. Optional 240 Volt Plug27 .. SECTION 8 MAINTENANCE (ONAN-POWERED UNITS)28 .. Maintenance (Onan-Powered Units)28 .. Label (Onan-Powered Units)29 .. Air Cleaner (Onan-Powered Units)30 .. Protection (Onan-Powered Units)30 .. Engine Oil, Oil Filter, and Fuel Filter (Onan-Powered Units)31 .. Engine Speed (Onan-Powered Units)32 .. Optional Spark Arrestor (Onan-Powered Units)33 .. TABLE OF CONTENTSSECTION 9 MAINTENANCE (KOHLER-POWERED UNITS)33.

6 Label (Kohler-Powered Units)33 .. Maintenance (Kohler-Powered Units)34 .. Air Cleaner (Kohler-Powered Units)35 .. Engine Oil, Oil Filter, and Fuel Filter (Kohler-Powered Units)36 .. Engine Speed (Kohler-Powered Units)37 .. Protection (Kohler-Powered Units)38 .. Optional Spark Arrestor (Kohler-Powered Units)38 .. SECTION 10 TROUBLESHOOTING39 .. SECTION 11 ELECTRICAL DIAGRAMS42 .. SECTION 12 GENERATOR POWER GUIDELINES44 .. SECTION 13 STICK WELDING (SMAW) GUIDELINES51 .. SECTION 14 MIG WELDING (GMAW) GUIDELINES59 .. 14-1. Typical MIG Process Connections Using A Voltage-Sensing Wire Feeder59 .. 14-2. Typical MIG Process Connections Using A Constant Speed Wire Feeder59 .. 14-3. Typical MIG Process Control Settings60 .. And Positioning Welding Gun61.

7 That Affect Weld Bead Shape62 .. Movement During Welding63 .. Weld Bead Characteristics63 .. Weld Bead Characteristics63 .. 14-9. Troubleshooting Excessive Spatter64 .. Porosity64 .. Excessive Penetration64 .. Lack Of Penetration65 .. Incomplete Fusion65 .. Burn-Through65 .. Waviness Of Bead66 .. Distortion66 .. MIG Shielding Gases67 .. SECTION 15 PARTS LIST68 .. OPTIONS AND ACCESSORIESWARRANTYOM-4403 Page 1 SECTION 1 SAFETY PRECAUTIONS READ BEFORE USINGrom _nd_8/03 Warning: Protect yourself and others from injury read and follow these Symbol UsageMeans Warning! Watch Out! There are possible hazardswith this procedure! The possible hazards are shown inthe adjoining symbols. Marks a special safety message. Means Note ; not safety group of symbols means Warning!

8 Watch Out! possibleELECTRIC SHOCK, MOVING PARTS, and HOT PARTS symbols and related instructions below for necessary actionsto avoid the Arc Welding Hazards The symbols shown below are used throughout this manual tocall attention to and identify possible hazards. When you see thesymbol, watch out, and follow the related instructions to avoid thehazard. The safety information given below is only a summary ofthe more complete safety information found in the Safety Stan-dards listed in Section 1-7. Read and follow all Safety Standards. Only qualified persons should install, operate, maintain, and re-pair this unit. During operation, keep everybody, especially children, live electrical parts can cause fatal shocks orsevere burns. The electrode and work circuit is electricallylive whenever the output is on.

9 The input power circuit andmachine internal circuits are also live when power is on. In semiautomatic orautomatic wire welding, the wire, wire reel, drive roll housing, and all metalparts touching the welding wire are electrically live. Incorrectly installed orimproperly grounded equipment is a SHOCK can kill. Do not touch live electrical parts. Wear dry, hole-free insulating gloves and body protection. Insulate yourself from work and ground using dry insulating mats or coversbig enough to prevent any physical contact with the work or ground. Do not use AC output in damp areas, if movement is confined, or if there is adanger of falling. Use AC output ONLY if required for the welding process. If AC output is required, use remote output control if present on unit.

10 Additional safety precautions are required when any of the following electri-cally hazardous conditions are present: in damp locations or while wearingwet clothing; on metal structures such as floors, gratings, or scaffolds;when in cramped positions such as sitting, kneeling, or lying; or when thereis a high risk of unavoidable or accidental contact with the workpiece orground. For these conditions, use the following equipment in order present-ed: 1) a semiautomatic DC constant voltage (wire) welder, 2) a DC manual(stick) welder, or 3) an AC welder with reduced open-circuit voltage. In mostsituations, use of a DC, constant voltage wire welder is , do not work alone! Disconnect input power or stop engine before installing or servicing thisequipment. Lockout/tagout input power according to OSHA 29 (see Safety Standards).