TROUBLESHOOTING | ||
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CONTROL PC BOARD CALIBRATION
CAUTION
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 | |
Voltage Trimmers | |||
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MAX | MIN | Variable | |
Voltage Trimmers | |||
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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.
