Lincoln Electric V205-T Theory of Operation, General Description, Input Board and BUS Board

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E-2 E-2

THEORY OF OPERATION

FIGURE E.2 – GENERAL DESCRIPTION, INPUT BOARD & BUS BOARD

Fan

Superimposition

board

24 VDC

Bus board

AC DC Gate drive signals

Input

HF

board

board

Voltage Feedback

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

info.reconnect

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

ckt.AConturn

+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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GENERAL DESCRIPTION

The Invertec V205T AC/DC is an inverter based indus- trial welding power source that utilizes single-phase input power to produce constant current AC or DC output for both Stick (SMAW) and TIG (GTAW). With 230VAC input applied the V205T is rated at 200 amps, 18volts at a 40% duty cycle. With 115VAC applied the machine is rated at 150 amps, 16 volts at a 40% duty cycle. The machine has the capabilities to produce several varieties of AC waveforms (square, sinusoidal and triangular). The unit also employs an auto recon- nect feature that does not require manual intervention when the input power is changed from 115VAC to 230VAC or 230VAC to 115VAC. When in the TIG mode the operator may select to use either the high frequen- cy or touch start function.

INPUT BOARD AND BUS BOARD

The single phase input voltage is applied to the V205T through a line switch located on the back of the machine. The AC input voltage is filtered and condi- tioned by a network of inductors, capacitors and a varistor that are all located on the Input Board. This fil-

tered input voltage is applied to the Main IGBT Inverter Board. Another function of the Input Board is to pre- vent high frequency inverter generated “noise” from being induced back into the supply lines.

The Bus Board performs several functions within the V205T. It accepts and distributes power and informa- tion to other circuitry. This interfacing is accomplished through harness and ribbon connectors and also via other PC boards that are plugged directly into the Bus Board. The Input Board, the High Frequency Board and the AC Super-Imposition Board plug into the Bus Board. Circuitry located on the Main IGBT Inverter Board, the Control Board, the Output Module Board, the Output Filter Board and the Hall Effect Device interface with the Bus Board. Some circuits are also incorporated within the Bus Board. They are the fan circuit (24VDC) and an input voltage sensing circuit that is utilized by the auto reconnect circuitry located on the Main Inverter Board.

The fan fuse F3, the 400VDC fuse F2 and the water cooler F1 (not used) are also located on the Bus Board.

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

V205-T AC/DC