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E-4

THEORY OF OPERATION

E-4

 

FIGURE E.4 - MAIN TRANSFORMER, OUTPUT DIODE MODULE & CLAMPING BOARD,

OUTPUT TRANSISTOR MODULE & SUPERIMPOSITION BOARD

Fan

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Superimposition

 

 

 

 

 

 

 

 

 

 

 

 

board

 

 

 

 

 

 

 

 

 

 

 

24 VDC

Bus board

 

 

 

 

 

 

 

 

 

AC DC Gate drive signals

 

 

 

Input

 

 

 

 

 

 

 

 

 

HF

 

 

 

 

 

 

 

 

 

 

 

 

 

 

board

 

 

 

 

 

board

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Voltage Feedback

 

 

 

 

 

15,+5-+24,+15,48,-

.inforeconnect

ckt.AConturn

supplyvolthigh

feedbackvoltage

feedbackcurrent

 

 

 

 

Current Feedback

 

 

 

 

 

 

 

 

 

Output

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

IGBT

 

Diode

 

 

 

 

 

 

 

 

 

 

 

 

 

Thermostat

 

 

 

Output

 

 

 

 

 

 

 

Thermostats

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Filter bd.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

(bypass)

 

Main IGBT

 

 

 

 

 

 

 

 

 

 

 

 

 

& Power board

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

4

 

 

 

 

 

 

_

 

 

 

 

 

 

 

 

IGBT's

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Output

RF coil

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Choke

+

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

infothermostat

metervoltinput

metercurrentinput

 

DC blocking

 

 

Current

 

 

 

 

 

.cktAConturn

+515,+15,-

infoset

PWMonturn

capacitor board

 

 

 

 

 

Input

 

 

 

Hall

 

 

 

 

 

 

 

 

 

 

 

Main

 

Output

 

 

 

Choke

 

 

 

 

 

 

 

Output

Device

 

 

 

 

 

 

 

 

 

 

 

 

Transformer

board

Transistor

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Module

 

 

 

 

 

 

 

 

 

 

 

 

 

24 VDC Remote 2/4 path (D + E)

 

 

 

 

HF control signal

 

 

 

 

 

 

 

888

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

+48, +24

 

 

 

 

 

Control board

Display & LED

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

board

 

 

 

 

Control

(D + E)

Remote 2/4

Knob

 

Remote

48 VDC75, 76, 77 A, B, C

Gas

Solenoid

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MAIN TRANSFORMER

The 100KHZ output of the Main IGBT Inverter Board is coupled, through a DC Blocking Capacitor Board, to the primary of the Main Transformer. The transformer reduces the high voltage (low current) input applied to the primary winding and through transformer action develops a lower secondary voltage capable of high output currents.

OUTPUT MODULE TRANSISTOR BOARD

This module produces the AC waveforms and frequen- cies. It receives command signals from the Superimposition Board. Depending on which of the two IGBTs is active at any given moment the welding output of the machine can be either positive or nega- tive AC or DC.

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OUTPUT MODULE AND CLAMPING BOARD

The AC output of the Main Transformer is applied to the Output Modules for full wave rectification. The Clamping Diodes function as a filter eliminating any pulsed over-voltages that may be present at the Output Modules. The Clamping Board protects the Output Modules from damage due to higher than normal volt- age spikes.

SUPERIMPOSITION BOARD

The Super Imposition Board receives signals from the Control/Display Board to control the status of the sec- ondary inverter portion of the V205T machine. This board also generates voltage pulses at about +/- 200VDC that facilitate the re-striking of the arc when the TIG AC welding current is being utilized. The Superimposition Board internally generates the auxil- iary power supply for the isolated piloting of the power elements (IGBTs) for the Output Module Transistor Board. The Superimposition Board plugs directly into the Bus Board.

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NOTE: Unshaded areas of Block Logic Diagram are the subject of discussion

INVERTEC® V205-T AC/DC™

Page 38
Image 38
Lincoln Electric SVM161-A service manual Main Transformer, Output Module Transistor Board, Output Module and Clamping Board