Miller Bobcat 250 NT Page 1 Owner'S Manual Download

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Bobcat 250 NT

Processes

Description



Non-Critical TIG (GTAW)
Welding

Stick (SMAW) Welding

MIG (GMAW) Welding
Flux Cored (FCAW) Welding

Engine Driven Welding Generator

OM-4403

200 291E

April 2002

Visit our website at

www.MillerWelds.com

Summary of Contents for Bobcat 250 NT

Page 1: ...Processes Description Non Critical TIG GTAW Welding Stick SMAW Welding MIG GMAW Welding Flux Cored FCAW Welding Engine Driven Welding Generator OM 4403 200 291E April 2002 Visit our website at www Mi...

Page 2: ...value established in 1929 This Owner s Manual is designed to help you get the most out of your Miller products Please take time to read the Safety precautions They will help you protect yourself again...

Page 3: ...le Sizes 18 SECTION 5 OPERATING THE WELDING GENERATOR 19 5 1 Front Panel Controls 19 5 2 Typical Stick Welding Connections And Control Settings 20 5 3 Typical MIG Welding Connections And Settings 21 5...

Page 4: ...g And Positioning Welding Gun 61 13 5 Conditions That Affect Weld Bead Shape 62 13 6 Gun Movement During Welding 63 13 7 Poor Weld Bead Characteristics 63 13 8 Good Weld Bead Characteristics 63 13 9 T...

Page 5: ...n not in use Do not use worn damaged undersized or poorly spliced cables Do not drape cables over your body If earth grounding of the workpiece is required ground it directly with a separate cable Do...

Page 6: ...uch hot engine parts or just welded parts bare handed NOISE can damage hearing Noise from some processes or equipment can damage hearing Wear approved ear protection if noise level is high MAGNETIC FI...

Page 7: ...ammables Keep exhaust and exhaust pipes way from flammables EXHAUST SPARKS can cause fire Do not let engine exhaust sparks cause fire Use approved engine exhaust spark arrestor in required areas see a...

Page 8: ...une Rd Miami FL 33126 National Electrical Code NFPA Standard 70 from National Fire Protec tion Association Batterymarch Park Quincy MA 02269 Safe Handling of Compressed Gases in Cylinders CGA Pamphlet...

Page 9: ...oquer une lectrocution Mettre l appareil hors tension quand on ne l utilise pas Ne pas utiliser des c bles us s endommag s de grosseur insuffisante ou mal piss s Ne pas enrouler les c bles autour du c...

Page 10: ...pour travailler sur un moteur chaud Ne pas toucher mains nues les parties chaudes du moteur ni les pi ces r cemment soud es LE BRUIT peut affecter l ou e Le bruit des processus et des quipements peut...

Page 11: ...nir distance les produits inflammables de l chappement LES TINCELLES L CHAPPEMENT peuvent provoquer un incendie Emp cher les tincelles d chappement du moteur de provoquer un incendie Utiliser uniqueme...

Page 12: ...W Lejeune Rd Miami FL 33126 National Electrical Code NFPA Standard 70 de la National Fire Protec tion Association Batterymarch Park Quincy MA 02269 Safe Handling of Compressed Gases in Cylinders CGA P...

Page 13: ...Engine Specifications This unit uses either an Onan Performer OHV or a Kohler CH 20 engine Differences between models are noted throughout this manual Note Welding Mode Weld Output Range Rated Weldin...

Page 14: ...18 in 457 mm G Do not move or operate unit where it could tip B 16 1 2 in 419 mm 4 Holes tip C 3 4 in 19 mm E D 3 1 8 in 79 mm F 25 E 32 3 4 in 832 mm 25 F 45 1 2 in 1156 mm 25 25 G 13 32 in 10 mm Di...

Page 15: ...OM 4403 Page 11 3 4 Fuel Consumption Onan Powered Units 206 148 3 5 Fuel Consumption Kohler Powered Units 200 299...

Page 16: ...6 200 297 200 298 The volt ampere curve shows the minimum and maximum voltage and amperage output capabilities of the welding generator Curves of all other settings fall between the curves shown A For...

Page 17: ...ways securely fasten welding generator onto transport vehicle or trailer and comply with all DOT and other applicable codes Always ground generator frame to vehicle frame to pre vent electric shock an...

Page 18: ...en and do not use the oil pressure shutdown system to monitor oil level Fuel Add fresh fuel before starting engine the first time see mainte nance label for specifications Al ways leave filler neck em...

Page 19: ...en and do not use the oil pressure shutdown system to monitor oil level Fuel Add fresh fuel before starting engine the first time see mainte nance label for specifications Al ways leave filler neck em...

Page 20: ...Wait ten minutes and check electro lyte level If necessary add electro lyte to raise to proper level Reins tall vent caps 6 Battery Charger Read and follow all instruc tions supplied with battery char...

Page 21: ...6 Installing Exhaust Pipe 801 681 Ref 200 017 Engine backfire can cause se vere burns or other injuries Do not point exhaust pipe toward control panel Keep away from exhaust outlet Point exhaust pipe...

Page 22: ...dersized or poorly spliced cables Welding Amperes 10 60 Duty Cycle 60 100 Duty Cycle 10 100 Duty Cycle 100 4 20 4 20 4 20 3 30 2 35 1 50 1 0 60 1 0 60 150 3 30 3 30 2 35 1 50 1 0 60 2 0 70 3 0 95 3 0...

Page 23: ...ct type of weld output Use a positive position for Direct Current Electrode Positive DCEP and a negative position for Direct Current Electrode Negative Use AC position for alternating current 5 Coarse...

Page 24: ...Weld Process Selector switch to Stick position Set Coarse Range switch to 60 140 1 8 position Set Fine control at 7 or higher for best results 1 2 ELECTRODE DC AC POSITION PENETRATION USAGE MIN PREP R...

Page 25: ...ching Tighten knob See wire feeder manual for wire thread ing procedure Insert gun trigger plug item 4 into matching receptacle and tighten threaded collar Connect gas hose from feeder to regula tor o...

Page 26: ...r and position as close as possible to drive rolls without touching Tight en knob See wire feeder manual for wire threadingprocedure Insert gun trigger plug item 4 into matching receptacle and tighten...

Page 27: ...weld control receptacle Tighten threaded collar Connect ac power cord item 12 to 120 volt ac receptacle on welding generator Connect gas hose from spoolgun to regula tor on Argon bottle Reinstall weld...

Page 28: ...CB1 and CB2 protect RC1 from over load If CB1 or CB2 opens RC1 and one of the 120 volt receptacles does not work 120 volts may still be pres ent at RC1 Power is still present at the 240 volt receptacl...

Page 29: ...detected the GFCI Reset button pops out and the circuit opens to dis connect the faulty equipment Check for damaged tools cords plugs etc con nected to the receptacle Press button to re set receptacl...

Page 30: ...20 V loads 7 Current Available in Amperes 240 V Receptacle Each 120 V Duplex Receptacle V x A Watts 42 37 32 27 22 0 5 10 15 20 Tools Needed SECTION 7 MAINTENANCE ONAN POWERED UNITS 7 1 Routine Mainte...

Page 31: ...r cleaner element See Section 7 3 200 h Replace fuel filter See Section 7 5 Change oil filter See Section 7 5 and maintenancelabel Check spark plugs Replace unreadable labels 500 h Repair or replace c...

Page 32: ...OM 4403 Page 28 7 2 Maintenance Label Onan Powered Units...

Page 33: ...Powered Units 802 921 B Stop engine Disconnect negative battery cable 1 Fuse F1 See Parts List F1 protects the weld excitation winding from overload If F1 opens weld output stops or is low 2 Fuse F2...

Page 34: ...rd ing to engine owner s manual Close valve and valve cap before adding oil and running engine Fill crankcase with new oil to full mark on dipstick see Section 7 2 4 Fuel Filter 5 Fuel Line Replace li...

Page 35: ...screws Adjust solenoid position so engine runs at idle speed If necessary back out idle speed screw so solenoid can be moved to correct position Tight en mounting screws Be sure sole noid linkage wor...

Page 36: ...its Follow the storage procedure in the engine owner s manual if the unit will not be used for an extended period Note Recycle engine fluids Stop engine before maintaining See also Engine Manual and m...

Page 37: ...tem See Engine Manual 200 h Replace fuel filter See Section 8 4 Change oil filter See Section 8 4 and maintenance label Replace unreadable labels Check spark plugs 500 h Repair or replace cracked cabl...

Page 38: ...822 Ref 200 017 S 0759 Stop engine Do not run engine without air cleaner or with dirty element 1 Wrapper Foam Element Wash wrapper with soap and water solution Allow wrapper to air dry completely Spr...

Page 39: ...ine oil and filter accord ing to engine owner s manual Close valve and valve cap before adding oil and running engine Fill crankcase with new oil to full mark on dipstick see Section 8 2 4 Fuel Filter...

Page 40: ...ews 3 Idle Speed Screw Loosen mounting screws Adjust solenoid position so engine runs at idle speed If necessary back out idle speed screw so solenoid can be moved to correct position Tight en mountin...

Page 41: ...ower output stops or is low 3 Fuse F6 See Parts List F6 protects the engine wiring sys tem from overload If F6 opens engine will not crank Replace any open fuses Reinstall cover before operating If a...

Page 42: ...ol settings Check engine speed and adjust if necessary see Section 7 6 or 8 5 Erratic weld output Check control settings Tighten and clean connections to electrode and workpiece Use dry properly store...

Page 43: ...arts List for location Have Factory Authorized Service Agent check fuel shutoff solenoid FS1 FS1 optional on Onan powered units Engine starts but stops when Engine Check oil level Control switch retur...

Page 44: ...or smooth operation Tune up engine according to engine manual Engine does not return to idle speed Remove weld and generator power loads Check throttle linkage for smooth non binding operation Have Fa...

Page 45: ...OM 4403 Page 41 Notes...

Page 46: ...OM 4403 Page 42 SECTION 10 ELECTRICAL DIAGRAMS Figure 11 1 Circuit Diagram For Welding Generator...

Page 47: ...OM 4403 Page 43 202 547 D...

Page 48: ...s symbol and or wording 3 1 11 2 Grounding Generator To Truck Or Trailer Frame S 0854 Always ground generator frame to vehicle frame to pre vent electric shock and static electricity hazards 1 Generat...

Page 49: ...sistive Load Equipmentwith a motor is a non re sistive load and requires approxi mately six times more power while starting the motor than when run ning see Section 11 8 3 Rating Data Rating shows vol...

Page 50: ...Home Equipment Rating Starting Watts Running Watts Stock Tank De Icer 1000 1000 Grain Cleaner 1 4 HP 1650 650 Portable Conveyor 1 2 HP 3400 1000 Grain Elevator 3 4 HP 4400 1400 Milk Cooler 2900 1100 M...

Page 51: ...P 6000 1500 1 1 2 HP 8200 2200 2 HP 10500 2800 Electric Chain Saw 1 1 2 HP 12 in 1100 1100 2 HP 14 in 1100 1100 Electric Trimmer Standard 9 in 350 350 Heavy Duty 12 in 500 500 Electric Cultivator 1 3...

Page 52: ...r Starting Requirements Motor Start Code G H J K L M N P KVA HP 6 3 7 1 8 0 9 0 10 0 11 2 12 5 14 0 EXAMPLE Calculate the starting amperage required for a 230 V 1 4 HP motor with a motor start code of...

Page 53: ...ergency Disconnect Allows the utility power to be quickly disconnected from the building electrical system 6 Extension Cord Select as shown in Section 11 11 7 Generator Connections Connect terminals o...

Page 54: ...15 40 4800 112 34 62 19 37 11 45 5400 100 30 62 19 50 6000 87 26 50 15 Conductor size is based on maximum 2 voltage drop Cord Lengths for 240 Volt Loads If unit does not have GFCI receptacles use GFC...

Page 55: ...s clean be fore welding 2 Work Clamp 3 Electrode A small diameter electrode requires less current than a large one Fol low electrode manufacturer s instructions when setting weld am perage see Section...

Page 56: ...LET ALL ALL EP EP EP EN EP EN EP EP EN EP EP 6010 6011 6013 7014 7018 7024 NI CL 308L EP ELECTRODE POSITIVE REVERSE POLARITY EN ELECTRODE NEGATIVE STRAIGHT POLARITY ELECTRODE AMPERAGE RANGE DIAMETER 1...

Page 57: ...12 6 Poor Weld Bead Characteristics S 0053 A 1 Large Spatter Deposits 2 Rough Uneven Bead 3 Slight Crater During Welding 4 Bad Overlap 5 Poor Penetration 5 4 2 3 1 12 7 Good Weld Bead Characteristics...

Page 58: ...orrect Angle 12 9 Electrode Movement During Welding Normally a single stringer bead is satisfactory for most narrow groove weld joints however for wide groove weld joints or bridging across gaps a wea...

Page 59: ...3 4 12 11 Lap Joint S 0063 S 0064 1 Electrode 2 Single LayerFillet Weld Move electrode in circular motion 3 Multi Layer Fillet Weld Weld a second layer when a heavi er fillet is needed Remove slag be...

Page 60: ...Causes Corrective Actions Arc length too long Reduce arc length Damp electrode Use dry electrode Workpiece dirty Remove all grease oil moisture rust paint coatings slag and dirt from work surface bef...

Page 61: ...dirt from work surface before welding 12 17 Troubleshooting Lack Of Penetration Lack Of Penetration shallow fusion between weld metal and base metal Lack of Penetration Good Penetration Possible Cause...

Page 62: ...llel and does not cover joint formed by base metal Possible Causes Corrective Actions Unsteady hand Use two hands Practice technique 12 21 Troubleshooting Distortion Distortion contraction of weld met...

Page 63: ...For GMAW use optional gas valve Voltage Sensing Wire Feeder Constant Current CC Or Constant Voltage CV Power Source Work Lead Electrode Lead Workpiece Work Clamp Voltage Sensing Clamp Gun 802 488 13 2...

Page 64: ...35 in 40 145 A 50 180 A 035 in Select Wire Speed Select Voltage Wire Recommendation 030 in 035 in 2 in per ampere 1 6 in per ampere Wire Speed 2 x 125 A 250 ipm 1 6 x 125 A 200 ipm Set voltage midway...

Page 65: ...3 mm past end of nozzle and tip of wire is positioned correctly on seam NOTE 1 Hold Gun and Control Gun Trigger 2 Workpiece 3 Work Clamp 4 Electrode Extension Stickout 1 4 to 1 2 in 6 To 13 mm 5 Cradl...

Page 66: ...trode extension stickout travel speed thickness of base metal wire feed speed weld current and voltage NOTE Short Normal Long Short Normal Long 10 10 GUN ANGLES AND WELD BEAD PROFILES ELECTRODE EXTENS...

Page 67: ...nt Along Seam 3 Weave Patterns Use weave patterns to cover a wide area in one pass of the electrode S 0054 A 3 1 2 13 7 Poor Weld Bead Characteristics 1 Large Spatter Deposits 2 Rough Uneven Bead 3 Sl...

Page 68: ...nsufficient shielding gas at welding arc Increase flow of shielding gas at regulator flowmeter and or prevent drafts near welding arc Remove spatter from gun nozzle Check gas hoses for leaks Place noz...

Page 69: ...n Incomplete Fusion failure of weld metal to fuse completely with base metal or a preceeding weld bead S 0637 Possible Causes Corrective Actions Workpiece dirty Remove all grease oil moisture rust pai...

Page 70: ...pport hand on solid surface or use two hands 13 16 Troubleshooting Distortion Distortion contraction of weld metal during welding that forces base metal to move Base metal moves in the direction of th...

Page 71: ...uminum Short Circuiting Aluminum Argon All Positions5 All Positions Argon 1 O2 Flat Horizontal5 Fillet Flat Horizontal5 Fillet Argon 2 O2 Flat Horizontal5 Fillet Flat Horizontal5 Fillet Argon 5 O2 Fla...

Page 72: ...s common and not available unless listed Figure 14 1 Main Assembly Onan OHV Engine Shown 42 FIG 14 3 41 39 43 40 44 45 31 28 36 32 37 38 33 34 35 51 50 52 1 2 3 4 9 8 6 5 27 22 21 23 24 26 25 30 13 46...

Page 73: ...1 F6 021 718 Fuse Mintr Gl 30a 32v 1 180 096 Tune Up Filter Kit Kohler CH 20 1 066 698 Oil Filter 1 121 652 Filter Clamps Fuel 1 067 272 Element Air Cleaner 1 067 273 Air Filter Wrapper 1 067 007 Spar...

Page 74: ...el Front W Components 1 43 CT1 201 784 Transformer Current Sensing 1 44 177 136 Clamp Capacitor 1 375dia Clip 1 45 C1 199 979 Capacitor Elctlt 1500uf 75vdc Can 1 40 Dia 1 46 D4 135 184 Diode Board 1 4...

Page 75: ...Onan OHV 4 6 186 083 Screw 437 14x1 75 Hexwhd 93d Gr8 Pld Kohler CH 20 4 7 198 461 Rotor Generator Consisting Of 1 8 181 134 Fan Rotor Gen 1 9 181 143 Bearing Ball Rdl Sgl Row 984 X 2 047 X 59 1 10 2...

Page 76: ...To Idle 5 Pin 1 7 R1 200 657 Rheostat Ww 150w 14 Ohm 1 8 S2 176 606 Switch Ignition 1 9 RC2 3 141 432 Receptacle Str Dx Grd 2p3w 20a 125vac 2 9 GFCI 2 3 151 981 Receptacle Str Dx Grd 2p3w 15 20a 125va...

Page 77: ...l 1 21 147 195 Nut 375 27 Nyl 4 22 RC1 182 954 Receptacle Str 3p4w 50a 125 250vac 1 119 172 Plug Str 50a 125 250v 1 23 188 039 Cover Receptacle CSA 1 24 148 956 Handle Switch 2 25 097 924 Knob Pointer...

Page 78: ......

Page 79: ...tting Torches Remote Controls Accessory Kits Replacement Parts No labor Spoolmate Spoolguns Canvas Covers Miller s True Blue Limited Warranty shall not apply to 1 Consumable components such as contact...

Page 80: ...complete and retain with your personal records Always provide Model Name and Serial Style Number Call 1 800 4 A Miller or see our website at www MillerWelds com to locate a DISTRIBUTOR or SERVICE AGEN...

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