Theory of operation, Power source general description, Input voltage and precharge – Lincoln Electric INVERTEC SVM199-A User Manual
Page 34
THEORY OF OPERATION
E-2
E-2
INVERTEC® V450-PRO
POWER SOURCE
GENERAL DESCRIPTION
The INVERTEC® V450-PRO is an inverter based
welding power source that is designed to be a multi-
process welding system. It is a high performance, dig-
itally controlled inverter capable of complex, high-
speed waveform control. With the appropriate modu-
lar components it can support constant current, con-
stant voltage and pulse welding processes. The output
rating is 450 amps at 36 volts with a 100% duty cycle.
INPUT VOLTAGE AND
PRECHARGE
The INVERTEC® V450-PRO can be connected for a
variety of three phase voltages. Refer to Figure E.2.
The initial input power is applied to the INVERTEC®
V450-PRO through a line switch located on the front of
the machine. Two phases of the three-phase input
power is applied to the input board and both auxiliary
transformers. The various secondary voltages devel-
oped by the #1 auxiliary transformer are applied to the
input board, the power board rectifier and the fan
motor. The 115 VAC secondary voltage developed by
the No. 2 auxiliary transformer is applied to the 115
VAC receptacle.
FIGURE E.2 - INPUT VOLTAGE AND PRECHARGE.
The 65 VDC produced from the power board rectifier is
utilized by the power board to provide various DC volt-
ages for the control board and wire feeder.
The two phases, which are connected to the input
board through the power switch, are connected to the
input rectifier. During precharge or “soft start” these
two phases are current limited by the input board. This
AC input voltage is rectified, and the resultant DC volt-
age is applied through the reconnect switches to the
input capacitors located on the switch boards. The
control board monitors the voltage across the capaci-
tors. When the capacitors have charged to an accept-
able level, the control board signals the input board to
energize the main input contactor making all three
phases of input power, without current limiting, avail-
able to the input capacitors. At this point, the
INVERTEC® V450-PRO is in the “Run Mode” of oper-
ation. If the capacitors become under or overvoltage,
the control board will signal the input board to de-
energize the main input contactor, and the
INVERTEC® V450-PRO will be disabled.
NOTE: Unshaded areas of Block Logic
Diagram are the subject of discussion
INPUT
CONTACTOR
INPUT
RECTIFIER
R
E
C
O
N
N
E
C
T
CONTROL BOARD
RIGHT
SWITCH
BOARD
LEFT
SWITCH
BOARD
MAIN
TRANSFORMER
CURRENT
SENSOR
CHOKE
OUTPUT
TERMINAL
OUTPUT
TERMINAL
POWER
BOARD
115VAC
RECEPTACLE
P
O
W
E
R
S
W
I
T
C
H
I
N
P
U
T
B
O
A
R
D
FAN
MOTOR
AUX.
TRANS.
AUX.
TRANS.
RECTIFIER
AUX.
RECONNECT
PRIMARY
CURRENT
SENSOR
WIRE FEEDER
RECEPTACLE
RS232
CONN.
THERMOSTATS
STATUS
LIGHT
THERMAL
LIGHT
CURRENT FEEDBACK
VOLTAGE FEEDBACK
65VDC
40VDC
CONTROL SIGNALS
PWM
CAPACITOR
VOLTAGE
FEEDBACK
PWM
DRIVE
VOLTAGE
SENSE
RECEPTACLE
#1
#2
S
W
I
T
C
H
DRIVE
FEEDBACK
VOLTAGE
CAPACITOR
INPUT
CONTACTOR
INPUT
RECTIFIER
R
E
C
O
N
N
E
C
T
CONTROL BOARD
RIGHT
SWITCH
BOARD
LEFT
SWITCH
BOARD
MAIN
TRANSFORMER
CURRENT
SENSOR
CHOKE
OUTPUT
TERMINAL
OUTPUT
TERMINAL
POWER
BOARD
115VAC
RECEPTACLE
P
O
W
E
R
S
W
I
T
C
H
I
N
P
U
T
B
O
A
R
D
FAN
MOTOR
AUX.
TRANS.
AUX.
TRANS.
RECTIFIER
AUX.
RECONNECT
PRIMARY
CURRENT
SENSOR
WIRE FEEDER
RECEPTACLE
RS232
CONN.
THERMOSTATS
STATUS
LIGHT
THERMAL
LIGHT
CURRENT FEEDBACK
VOLTAGE FEEDBACK
65VDC
40VDC
CONTROL SIGNALS
PWM
CAPACITOR
VOLTAGE
FEEDBACK
PWM
DRIVE
VOLTAGE
SENSE
RECEPTACLE
#1
#2
S
W
I
T
C
H
DRIVE
FEEDBACK
VOLTAGE
CAPACITOR