Lincoln Electric SAM400 - Manual (Page 30)

E-7 TROUBLESHOOTING E-7
CONTROL PC BOARD CALIBRATION
THE SCR BRIDGE SHOULD BE CHECKED
BEFORE INSTALLING A NEW CONTROL BOARD.
COMPONENTS ON THE NEW CONTROL BOARD
COULD BE DAMAGED BY A DEFECTIVE SCR
BRIDGE.
NOTE: Before the PC Boards can be calibrated the
machine must be "hot".
That is, it should be run
approximately one hour at maximum O.C.V. with all
covers on the generator.
Factory replacement Control PC Boards are preset
and should require only minor adjustment if any.
1. Before any calibrations are made, the engine speed
must be correct. Check the engine speed as fol-
lows:
a) Set toggle switch to variable voltage.
b) Set variable voltage control and portable
field control to high.
c) Allow engine to warm up for approximately
15 minutes.
d) Using an accurate tachometer, check high
idle engine speed. It must be within limits
given on the nameplate. Adjust governor
only if absolutely necessary. To obtain an
accurate speed setting, the unit must be
generating its maximum open circuit voltage
(Step A.3 below). If no voltage is being gen-
erated, this trouble must be first corrected
before final speed setting is obtained.
MAX MIN Constant
-1- -2- Voltage Trimmers
MAX MIN Variable
-3- -4- Voltage Trimmers
A. Variable Voltage
1. Place toggle switch in variable voltage posi-
tion.
2. Turn variable voltage control and portable
field control to high.
3. Set Trimmer #3 so that OCV is 95±1 volts
DC on SAM400 machines or 89±1 volts for
SAM650 machines.
4. Turn variable voltage rheostat and portable
field control to low.
5. Set Trimmer #4 so that OCV is 65±1 volts
DC on SAM400 machines or 45±1 volts for
SAM650 machines. Recheck to make sure
readings fall within limits. Trimmer #4 set-
ting is dependent on Trimmer #3.
B. Constant Voltage
1. Place toggle switch in constant voltage
position.
2. Turn constant voltage rheostat and portable
field control to high.
3. Set Trimmer #1 so that OCV is 60±1 volts
DC on SAM400 machines or 68±1 volts for
SAM650 machines.
4. Turn constant voltage rheostat and portable
field control to low.
5. Set Trimmer #2 so that OCV is 21± 0.5 volts
DC on SAM400 machines or 22±0.5 volts
for SAM650 machines. Recheck to make
sure readings fall within limits. Trimmer #2
setting is dependent on Trimmer #1.
SAM400 & 650
CAUTION