Schematic - Entire Machine - Code 11209, 11210, 11211,11227 (G4617-1 - Lincoln Electric LF-72/74 Service Manual

G-7
SCHEMATIC - ENTIRE MACHINE - CODE 11209, 11210, 11211,11227 (G4617-1) LF-72
Coil
measures
21 ohms
Start-Up
On power-up, the LF-72 will light the
motor thermal LED for 0.5 seconds.
If the feeder is powered-up with the
trigger depressed, welding will not start
until the trigger is released and then
depressed again.
Control Board Summary
Has on-board power supply.
•
Receives switch signals from Trigger, Cold Feed, Gas Purge, Trigger
•
Interlock
Reads WFS potentiometer.
•
Communicates with optional timer kit to control burnback, postflow.
•
Controls motor speed with PWM.
•
Turns Gas Solenoid on, off.
•
Monitors motor current, lights yellow thermal LED if over 3.75 amps for an
•
extended time period. LED remains lit for 30 – 60 seconds to allow motor
to cool.
Does NOT support Run-in at this time.
•
Operates on 24-42 VAC. Maximum WFS and/or maximum pull force may
•
be less when operating at 24 VAC.
• Does NOT operate on 115 VAC.
575
Off = 0 VDC
OCV = 59 VDC
575B
On = 7.7 VDC
575C
562
563
553
Located on
case back
GAS
SOLENOID
552
552B
552B
Located on
internal panel
552A
41 580 42
J6
L1
ARC CURRENT J
ARC VOLTAGE L
I 41
24-42VAC
K 42
G 75A
REMOTE
VOLTAGE F 76A
CONTROL
E 77A
SENSE 67
N
M
C 2
OUTPUT
CONTROL
D 4
575C
552
38VDC at 576
552A 563
42VAC input 577 551
550
with control 580 553 562
board
disconnected.
60VDC with
J1-5
J1-2 J1-6 J1-16 J1-8 J1-3 J1-13 J1-9 J1-1 J1-15 J1-12
control board
connected
+POWER
100K
ohm
+5V +5V
COM
BOARD
POWER
SUPPLY
COM +5V +15V
0.1 ohm
NOTE: This diagram is for reference only. It may not be accurate for all machines covered by this manual.
ELECTRICAL DIAGRAMS
Values for CV300. Others
may be different.
0 VDC @ 0 = 5.8 Arc Volts
6.6 VDC @ 10 = 40 ArcVolts
75A
76A
77A
Connector located
behind case front
577
576
575
Gearbox ratio is 2:47
Connector located
Motor resistance
Motor is at electrode
by sheet panel
is 1.5 ohms
potential
1 Motor is located
2 behind
L4
563 3 glastic panel
FEED
4
562 MOTOR / PLATE
GEARBOX
575B 5
6
551 7 B
8 W
550
1.6V @ 50 IPM
P5
30.6V @ 800 IPM
67
L2
b
POSTFLOW
POSTFLOW
TIME RANGE
POT.
.25 - 10 SEC
A c
5V SIGNAL
FIXED
c D GAS FLOW
PULSE
PREFLOW &
ENABLE
WIDTH
POSTFLOW TIMER
GENERATOR
LOGIC
BURNBACK
A b
POT
PREFLOW
TIME FIXED
L5
COM J60-6 J60-5 J60-8 J60-7 J60-1 J60-3
AT 30msec
Located on 606A
Timer Board Summary
Case Front 605
Has potentiometers for burnback and postflow.
•
Preflow fixed at 30msec.
•
Burnback range is 0 to 0.25 sec.
•
Postflow range is 0.25 to 10 sec.
•
Receives "Gas Flow Enable" signal.
•
Outputs 100 msec pulses to turn Gas Flow On, Gas
•
L3
Flow Off.
20 OHM = OUTPUT ENABLED
HIGH IMPEDANCE = OUTPUT DISABLED
MOLEX
INDEX
KEY
556 4 605
NOT USED NOT USED
554
2 606
+15V
J14-1 J14-9
J1-11 J1-4 J2-1 J2-2 J2-3 J2-4 J2-5 J2-6 J3-1 J3-2 J14-8 J14-14 J14-2 J14-5
750 ohm
+15V
20
ohm
MOV
OPEN = 0V
750 ohm
MACHINE
CLOSED = 8V
TRIGGER OUTPUT
ENABLE
+5V
MOTOR
VOLTAGE
+ POWER SENSE 0V = 0.02 SECONDS
5V = 0.25 SECONDS
BURNBACK
DRIVE
FET MOTOR
DRIVE
CIRCUIT
BRAKE
EXTERNAL
FET
GAS LOW = CONTROL AT CONTROL BOARD
HIGH = CONTROL AT TIMER BOARD
SOLENOID
CONTROL
MOTOR
CURRENT
SENSE
MICRO
SCALING
CONTROLLER
DO NOT USE
NOT FIELD PROGRAMMABLE
PROGRAM
TACH
0-5V PULSE SIGNAL
FILTER FEEDBACK
5V = OFF 200 ohm
FREQUENCY = SPEED
(NOT ACTIVE)
THERMAL 4V OR LESS = ON
LED
WIRE
0V = MIN SPEED
LOW = DISABLE
FEED
5V = MAX SPEED COLD HIGH = ENABLE
SPEED
FEED
200 ohm
SOLENOID LOW = DISABLE
GAS
GAS
FET HIGH = ENABLE
SOLENOID
PURGE
0.25
10K ohm
ohm
LOW = DISABLE
TRIGGER
HIGH = ENABLE
INTERLOCK
COMMON ANALOG P.C. BOARD
SCHEMATIC = G4559
REMOTE
1 75
CONTROL
10K/2W VOLTAGE
2 76
POTENTIOMETER
77
3 (OPTIONAL)
4
P7
3 577A
WIRE FEED
2 576A 10K/2W
SPEED
1 575A
CONTROL
4
POTENTIOMETER
0 VDC MIN. WFS
5
5 VDC MAX. WFS
6
P8
Connector located
behind case front
To Power Source Electrode Connection
TRIGGER
INPUT
556 A
B
554
C CONNECTOR
D
15V SIGNAL E
D
100 msec PULSES
TOGGLE GAS FLOW ON/OFF
COM
TIMER KIT
+15V
(OPTIONAL)
SCHEMATIC =
M20336
5 VDC
when lit
601
608
607
515A
B
15 VDC Open
0 VDC Closed
15 VDC Open
0 VDC Closed
558
W 589
601
608 515 587
607 15 VDC in
559
2 STEP
position
J14-4 J14-12 J14-13 J14-7 J14-10 J14-16 J14-11 J14-15 J14-3
+15V +15V
G-7
TRIGGER
J4
Located on
Case Front
THERMAL LED
Lights when motor
current exceeds 4
B
W Amps for an
extended time.
COLD FEED
Located on
558
Case Front
515A
S1
515
559
GAS PURGE
TRIGGER
INTERLOCK
Located on
Case Front
589
S2
587
Trigger Interlock does not
stop welding when the
2-STEP
arc is broken. Pull and
release to end the weld.
LF-72/74