Lincoln Electric SVM136-A service manual Overload Protection, Auxiliary Power

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B-7

B-7

OPERATION

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OVERLOAD PROTECTION

The power source is thermostatically protected with proximity thermostats against overload or insufficient cooling. One thermostat is located on the nose of the center bottom primary coil and a second thermostat is attached to the lead connecting the secondaries. Both thermostats are connected in series with 2-4 circuit. If the machine is overloaded, the primary thermostat will open, the output will be zero, the amber thermal pro- tection light will be on and the fan will continue to run. The secondary thermostat will open either with an excessive overload or insufficient cooling. The output will be zero, the amber protection light will be on and the fan will continue to run. When the thermostats reset, the protection light will be off.

The power source is also protected against overloads on the SCR bridge assembly through the solid state fault protection circuit. This circuit senses an overload on the power source and limits the output to approxi- mately 550 amps by phasing back the SCR’s.

Protection is provided to protect the circuitry from acci- dental grounds. If leads 75, 76, or 77 are accidentally “grounded” to the positive output lead, the output will be reduced to a low value, thus preventing any damage to the machine. If the ground occurs between 75, 76, 77 and the negative output lead, one of the PC board elec- tronic “self-restoring” fuses will blow, preventing any machine damage. After the ground is cleared, the fuses automatically reset within a few seconds.

AUXILIARY POWER

On machines above code 9400, the IDEALARC CV- 400 can provide nominally 115 volts AC and 42 volts AC auxiliary power for operating wire feeding equip- ment and other accessories. This power is available at the 14-pin amphenol on the control panel and/or at the terminal strip behind the hinged control panel on the case front. On the amphenol, 115 volts AC is available at pins A and J (Domestic and Export models only); 42 volts AC is available at pins I and K. On the terminal strip, 115 volts AC is available at terminals 31 and 32; 42 volts AC is not available at the terminal strip. The two circuits, 115 volts AC and 42 volts AC, are isolated; and each is protected by a 10 amp circuit breaker.

FRONT VIEW OF 14-PIN CONNECTOR

RECEPTACLE

 

K=42

A=32

J=31

B=GND

I=41

L

N

C=2

H=21

D=4

G=75

E=77

F=76

 

M

PIN

LEAD NO.

FUNCTION

A

32

115 VAC

B

GND

Chassis Connection

C

2

Trigger Circuit

D

4

Trigger Circuit

E

77

Output Control

F

76

Output Control

G

75

Output Control

H

21

Work Connection

I

41

42 VAC

J

31

115 VAC

K

42

42 VAC

L

---

---

M

---

---

N

---

---

 

 

 

IDEALARC CV-400

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Contents Idealarc CV-400 California Proposition 65 Warnings SafetyElectric Shock can kill Cylinder may explode if damaged Sûreté Pour Soudage a L’Arc Précautions DE SûretéMaster Table of Contents for ALL Sections Table of Contents Installation Section Technical Specifications Idealarc CV-400 InstallationSafety Precautions Location and VentilationLifting Input Supply Connections Ground ConnectionReturn to Input Wire and Fuse SizeConnect Electrode and Work Leads to Output Terminals Reconnect Procedure Output ConnectionsFigure A.5 Output Terminal Connections Connect Wire Feeders Table of Contents Operation Section Safety Instructions OperationOperating Instructions Design Features Operational Features and ControlsGeneral Description Recommended ProcessesLimitations Welding CapabilityFigure B.1 Case Front Controls Controls and SettingsRemote Control Welding OperationLocal Control Overload Protection Auxiliary PowerIdealarc CV-400 Table of Contents Accessories OPTIONS/ACCESSORIES Factory Installed OptionsField Installed Options Connecting the NA-3 to the Idealarc CV-400 Automatic Wire FeedersFeederterminal Connecting the NA-5 to the Idealarc CV-400Accessories Connecting the LN-7 to the Idealarc CV-400 Terminal Strip Semiautomatic Wire FeedersConnecting the LN-8 or LN-9 to the Idealarc CV-400 Idealarc CV-400 Table of Contents Maintenance Return to Return to Section TOC Safety Precautions Routine and Periodic MaintenanceFigure D.1 Idealarc CV-400 Table of Contents Theory of Operation Section Input Line VOLTAGE, Contactor and Main Transformer Theory of OperationOutput CONTROL, Rectification and Feedback Figure E.4 CV-400 Trigger and Thermal Light Circuit Protective Devices CircuitsFigure E.5 SCR Operation SCR OperationIdealarc CV-400 Table of Contents Troubleshooting & Repair Section HOW to USE Troubleshooting Guide Troubleshooting & RepairElectric Shock can kill PC Board Troubleshooting ProceduresOutput Problems Troubleshooting GuideOutput Problems SCR/Diode Perform the SCR/Diode Bridge SCR/Diode Rectifier Bridge Test Welding Problems Control Transformer T2 Voltage Test DescriptionMaterials Needed Control Transformer T2 Voltage Test Test ProcedureRight Side View Input Contactor Test Input Contactor Test Figure F.4 Input Contactor Test Connections Test for Contact ContinuityMain Transformer T1 Voltage Test Main Transformer T1 Voltage Test Figure F.6 Main Secondary Lead Test Points Blank Main Transformer T1 Voltage Test Static SCR/DIODE Rectifier Bridge Test Static SCR/DIODE Rectifier Bridge Test SCR Anode Remove ANY Insulating Paint Cathode SCR Active SCR Test Active SCR Test Figure F.15 Heat Sink Test Points Figure F.16 SCR Tester Circuit and SCR Connections Normal Open Circuit Voltage Waveform Maximum Output Setting no LoadTypical Output Voltage Waveform Machine Loaded Typical SCR Gate Voltage Waveform Maximum Output Setting no LoadONE Output SCR not Functioning Abnormal Output Voltage Waveform Machine LoadedDescription Input Contactor CR1 CLEANING/REPLACEMENTContactor Replacement Procedure Cleaning ProcedureFAN Motor and Blade Removal and Replacement Procedure FAN Motor and Blade Removal and ReplacementSCR/DIODE Rectifier Assembly Removal and Replacement Removal and Replacement SCR/DIODE Rectifier AssemblySCR Removal and Replacement SCR Removal and Replacement Figure F.21 1/2 Wide Leaf Spring Procedure for the 1/2 Inch Wide SpringClamping Procedure For 1/4-20 CAP Screws Clamping Procedure For 1/4-28 CAP ScrewsInch Wide Spring Procedure forAfter Replacing the SCRs Mounting of Stud Type Diodes To Aluminum Heat Sinks To Aluminum Heat Sinks Mounting of Stud Type DiodesMain Transformer Removal and Replacement Removal of Lift Bail Main Transformer Removal & ReplacementFigure F.26 Choke Removal Removal of Choke and TOP Iron AssemblyFigure F.27 Epoxy MIX Application Areas Reassembly of Transformer CoilsFigure F.28 Coil Lead Placement Figure F.30 Primary Thermostat Location Reassemble the Lift Bail Reassembling the Main Transformer Into the MachineInput Idle Amps and Watts Retest After RepairOpen Circuit Voltages Welding Output Load TestIdealarc CV-400 Section G Electrical DiagramsWiring Diagram Codes 10084, 10085 Wiring Diagram Code Control PC Board G2629-1 Layout Control PC Board G2629-1 Schematic Snubber Snubber PC Board M15370-3 Schematic Idealarc CV-400
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