Lincoln Electric V250-S Output Rectification Control, Figure E.4 Output Rectification and Control

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Section TOC

Master TOC

E-5E-5

THEORY OF OPERATION

FIGURE E.4 OUTPUT RECTIFICATION AND CONTROL

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INPUT

INPUTRECTIFIER LINE

SWITCH

"A"

L

E

A

D

FAN

MOTORS

R

E

C

O

N

N

E

C

T

S

W

I

T

C

H

18VAC

POWER BOARD		MAIN
POWER BOARD		TRANSFORMER
		TRANSFORMER
CR1
RELAY
IGBT
			POSITIVE
CAPACITOR			OUTPUT
			TERMINAL
IGBT
IGBT		SHUNT
IGBT
	CURRENT
	TRANSFORMER		NEGATIVE
			NEGATIVE
CAPACITOR		F	OUTPUT
		F	TERMINAL
		E	F
IGBT		E	E
		D	E
		B	D
		A	B
		C	A
O		K	C
V			C
E		THERMOSTATS	K
R		THERMOSTATS
V
O
L
T	IGBT GATE SIGNALS		THERMAL
A	IGBT GATE SIGNALS
G
E	PROTECTION SIGNAL	CONTROL BOARD	LIGHT
	PROTECTION SIGNAL		LIGHT
CR1 RELAY DRIVE SIGNAL

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AUXILIARY

TRANSFORMER

REMOTE

RECEPTACLE

	OUTPUT STRIKE ARC				LOCAL/
			MODE		LOCAL/
			MODE		REMOTE
	CONTROL CONTROL FORCE	SWITCH			REMOTE
	CONTROL				SWITCH
	CONTROL

OUTPUT RECTIFICATION

AND CONTROL

The AC output from the main transformer secondary is rectified to a DC output and applied to the output terminals. Output voltage and current feedback infor- mation, which is fed to the control board, is sensed at the output terminals and shunt. The control board monitors the panel controls and remote control recep- tacle and compares these commands to the feedback information to determine how the output should be controlled to optimized welding results. The control board controls the IGBT switching through pulse width modulation circuitry. See IGBT Operation Discussion in this section.

NOTE: Unshaded areas of block logic diagrams are the subject of discussion.

INVERTEC V250-S

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Contents Invertec V250-S Safety Fumes and Gases can be dangerous Electric Shock can killARC Rays can burn Welding Sparks can cause fire or explosion Cylinder may explode if damagedSûreté Pour Soudage a L’Arc Précautions DE SûretéMaster Table of Contents for ALL Sections Table of Contents Installation Section InstallationThree Phase Technical Specifications Invertec V250-SThree Phase Single Phase Select Suitable Location Safety PrecautionsInput Connections Power Input Connection for 50/60 HZ Machines Input Voltage Reconnect ProcedureInput Fuse and Supply Wire Output Connections Remote Control ReceptacleQuick Disconnect Plugs Output CablesInvertec V250-S Operation Gouging Sparks Safety InstructionsFigure B.1 Case Front Controls Controls and SettingsManual ARC Welding Stick Constant Current ProcessesAIR Carbon ARC Cutting TIG WeldingThermal Protection Parallel OperationOverload Protection Invertec V250-S Table of Contents Accessories Section AccessoriesCable Plugs Options / AccessoriesRemote Controls Table of Contents Maintenance Section MaintenanceFigure D.1 Location of Input Filter Capacitor Terminals Input Filter Capacitor Discharge ProcedureFilter Capacitor Conditioning Routine MaintenanceFigure D.2 Location of Maintenance Components Theory of Operation Table of Contents Theory of Operation SectionInput Line Voltage General DescriptionFigure E.2 Protection and PRE-CHARGE Circuits Precharge and ProtectionFigure E.3 Main Transformer Main TransformerFigure E.4 Output Rectification and Control Output Rectification ControlOverload Protection Protection CircuitsInsulated Gate Bipolar Transistor Igbt Operation Maximum Output Pulse Width ModulationMinimum Output Troubleshooting & Repair Oscilloscope Warning HOW to USE Troubleshooting GuideBoard can be dam- aged by static electricity PC Board Troubleshooting ProceduresCourse of Action Possible Areas Recommended SymptomsPerform the Control Board Voltage Checks Possible AreasCapacitor Balance Test Troubleshooting & Repair Perform the Output Diode Test Welding Problems Invertec V250-S Materials Needed Auxiliary Transformer TestTest Description Auxiliary Transformer Test Test ProcedureTable F.1 Auxiliary Transformer Test Points Auxiliary Transformer TestInvertec V250-S Input Rectifier Test Input Rectifier Test Test ProcedureTest Point Terminals Analog Meter X10 Range Table F.2 Input Rectifier Test PointsInvertec V250-S Power Board Resistance Test Test Description Power Board Resistance TestTable F.3 Power Board Resistance Test Points Power Board Resistance TestInvertec V250-S Output Diodes Test Figure F.4 Machine Output Terminals Output Diodes TestInvertec V250-S Diode Modules Power Board Voltage Test Figure F.8 Plug J6 on Power Board Power Board Voltage TestTest Conditions Table F.4. Power Board Voltage Test PointsAcceptable Test Description Invertec V250-S Control Board Voltage Test Figure F.9 Plugs J1-J5 on Control Board Control Board Voltage Test18VAC Table F.5. Control Board Voltage Test PointsInvertec V250-S Protection Circuit Test Figure F.10 Control Board Plug J2 Test Points Protection Circuit TestProtection Circuit Simplified Invertec V250-S Capacitor Balance Test Capacitor Balance Test Figure F.12 Power Board and Capacitor Test LocationsTable F.6 Capacitor Voltages Invertec V250-S Control Board Removal and Replacement V250S Control Control Board Removal and ReplacementProcedure Power Board Removal and Replacement Figure F.14 Power Board Lead Locations Power Board Removal and ReplacementPower Board Replacement Procedure Invertec V250-S Matched Parts Filter Capacitor Removal and ReplacementFigure F.15 Heatsink/Power Board Removal Filter Capacitor Removal and ReplacementPerform Power Board Replacement Procedure in this section Invertec V250-S Input Rectifier Bridge Removal and Replacement Figure F.16 Input Rectifier Lead Locations Input Rectifier Bridge Removal and ReplacementTroubleshooting & Repair Invertec V250-S Materials Needed Snubber Resistors Locking Tabs Invertec V250-S Wrench Allen type wrench Torque wrench Mounting Bolts Diode Modules Bolted Connections Troubleshooting & Repair Invertec V250-S Main Transformer Removal and Replacement Machine Codes below T3 Current Transformer Main Transformer Main Transformer Secondary Leads Figure F.22 Main Transformer Mountings Clear all leads and secure for case wrap-around assembly Invertec V250-S Main Transformer Removal and Replacement Machine Codes Above Figure F.23 Main Transformer Right Side Figure F.24 Main Transformer Left Side Figure F.25 Main Transformer Mountings Troubleshooting & Repair Invertec V250-S Minimum Acceptable Output AT Maximum Output Settings Maximum Acceptable Output AT Minimum Output SettingsRetest After Repair Input Idle Amps and Idle WattsInvertec V250-S Electrical Diagrams Invertec V250-S Invertec V250S Wiring Diagram Codes 10102Return to Section Wiring Diagram Codes 10187G2666 Control PC Board G2666 LayoutPower P.C. BD. Asbly Power PC Board G2684 LayoutRelay Coils Control PC Board G2666 SchematicFrom Control BD Power PC Board G2684 Schematic