Lincoln Electric SVM149-A service manual Figure E.3 Precharge and Protection

Models: SVM149-A

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Section TOC

Master TOC

E-3E-3

THEORY OF OPERATION

FIGURE E.3 – PRECHARGE AND PROTECTION

INPUT 115/230/1/50/60 VAC

L1 SW1 A 300uH

B

RL3

 

RL2

R1

 

RL2

10/10W

 

F1

 

1A/250V

RL2

 

 

 

 

 

 

 

1500uF/250V

Q1a,b,c

D10

Lout

BS1

 

 

 

 

 

 

IRG4BC30W

WRK

 

 

 

C26

 

 

 

240uH

8A

 

AC

AC

 

 

 

 

 

 

 

 

 

 

T2

 

 

 

 

 

 

 

 

15K/3W

 

SEC

 

+12VDC TRANSFER

 

CP

CP

 

R1

+

PRI

 

 

 

CP

 

 

 

 

 

C1a,b

 

D11

 

 

 

CP

CP

 

 

RL1

NZL (2)

 

CP

C12

 

 

 

 

 

 

 

 

 

 

 

 

 

15K/3W

 

 

 

 

 

 

AC

AC

 

R2

+

 

 

 

C14

 

 

C2a,b

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

WORK CLAMP

V1

RL2

RL1

 

R24

Q2a,b,c

6.8k/5W

IRG4BC30W

 

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FN1

230VAC

V2

 

 

NO

COM

NC

Purge Switch

115VAC

L1

T1

230V

RL1

115V

L1

Input

Voltage Board

12VDC

Air

Solenoid

1

 

 

 

 

 

 

 

 

 

 

 

 

 

1500uF/250V

 

 

 

 

 

SHUNT

EL (3)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

C13

SH- SH+

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

CN1

15VAC

 

CN2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

CN3

1

 

9

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1

2

15VAC

 

10

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2

3

SAFETY

 

5

 

 

 

 

 

 

 

 

 

 

 

 

 

 

3

4

+28VDC

 

6

 

 

 

 

 

 

 

 

 

 

 

 

 

 

4

5

SEC GND

 

3

 

 

 

 

 

 

 

 

 

 

 

 

Main Inverter Board

 

6

OVLOAD

 

22

 

 

 

 

 

 

 

 

 

 

 

 

 

7

115/230

 

2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

8

+12VDC

 

20

 

 

 

 

 

 

 

 

 

CN1

 

 

 

 

 

 

 

 

 

 

15 16 12 18 14 1

 

 

 

 

 

 

 

 

 

4

 

 

 

 

 

 

 

11 4

13 7

19 24 21 23 8

17

1

2

3

 

 

 

PS2

PS1

SEC GND OVLOAD

SAFETY

V+ EV1 +15Vrms

+12VDC

+8V SW +12VDC SW

SEC GND

OVLOAD

TRANSFER SW

TRANSFER

SOL 1 DRIVER

V OUT OUTPUT TRIGGER SOL 2 DRIVER

 

POT WIPER

POT CW

POT CCW

 

 

 

CN1

8

6

17 9

3

1

2

18 14 7

15 4

11 5

16 10 12 13

 

23 22 24

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Display LED's

Output Control

Control Board

PT

12VDC Solenoid 2

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PRECHARGE AND PROTECTION

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The input voltage is rectified by the input rectifier on the inverter board. The resultant DC voltage is applied to the filter capacitors through the automatic reconnect of the input board. The input board also contains precharging circuitry for the safe charging of the input filter capacitors. Once the capacitors are precharged the input board activates the RL3 input relay. This connects full input power to the filter capacitors. When the filter capacitors are fully charged they act as power supplies for the IGBT switching circuit. The IGBTs supply the main trans- former primary winding with DC current flow.

The inverter board also monitors the filter capacitors for overvoltage. If this occurs, the appropriate signal is sent to the control board to disable the machines output and to turn on the Thermal/Voltage Overload status LED. See IGBT Operation discussion and diagrams in this section.

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

PRO-CUT 25

Page 29
Image 29
Lincoln Electric SVM149-A service manual Figure E.3 Precharge and Protection