Lincoln Electric INVERTEC SVM158-A Service Manual page 89

F-39
CURRENT TRANSDUCER TEST (continued)
OUTPUT LOAD CURRENT
8. Check the feedback voltage from the current
transducer using a resistive load bank and
with the V350-PRO in mode 200. Mode 200 is
a constant current test mode. This mode can
be accessed from the front panel of the V350
by pressing and holding the Mode Select but-
ton while turning the machine on.
Machines with an Advanced Process Panels
do not have a mode select button. Use the
same procedure except hold in the Memory
button on the advanced process panel instead
of the mode select button. Then, rotate the
output knob while still holding the Mode Select
button in until the displays read "Mode 200".
Release the Mode Select Button and the
machine will be in mode 200. With the V350-
PRO in mode 200, apply the grid load across
the output of the V350-PRO, set machine out-
put to 300 amps and enable WELD TERMI-
NALS. Adjust the grid load to obtain 300
amps on the external ammeter and check
feedback voltages per Table F.5.
A. Pin 1 (lead 801) to Pin 6 (lead 806) should
read 2.4 VDC (machine loaded to 300
amps).
TROUBLESHOOTING AND REPAIR
TABLE F.5
300
250
200
150
100
NOTE:
V350-PRO
EXPECTED TRANSDUCER FEEDBACK
VOLTAGE
2.4
2.0
1.6
1.2
0.8
9. If for any reason the machine cannot be
loaded to 300 amps, Table F.5. shows what
feedback voltage is produced at various cur-
rent loads.
10. If the correct supply voltages are applied to
the current transducer, and with the machine
loaded, the feedback voltage is missing or not
correct the current transducer may be faulty.
Before replacing the current transducer, check
the leads and plugs between the control board
(J8) and the current transducer (J90). See The
Wiring Diagram. For access to plug J90 and
the current transducer refer to: Current
Transducer Removal and Replacement
Procedure.
11. Remove input power to the V350-PRO.
12. Replace the control box top and any cable ties
previously removed.
13. Install the case wraparound cover using the
5/16" nut driver.
F-39