Service manual

3. Electrical Parts
3-10
AVR is adjusted and set prior to delivery from factory. Accordingly, it is not necessary to adjust it
unless the machine equipped with a new AVR functions abnormally. If upon test operation, there is
any trouble such as voltage hunting, adjust it according to the following procedures.
Adjustment of AVR
1.Start engine, and adjust the frequency to 62.5Hz at no load operation.
2.Turn the voltage adjuster (hand trimmer) on the instrument panel fully to the right to the
maximum position.
3.Under this condition, turn the voltage adjuster of AVR in the control panel, using a driver, so that
the upper value of voltage may meet the value mentioned in the following table.
Notching position of voltage adjustment (VOLT.ADJ): 5.5/10 ※
Voltage
Frequency
240V 480V
62.5Hz 252V 504V
4.The driver slot of voltage adjusting volume of AVR should be coated with silicon caulking paste and
fully sealed.
Adjustment of stability
It is possible to adjust the response speed of generator output voltage at no load operation by the
adjusting volume knob of stability.
1.Turning the volume knob of stability adjustment clockwise reduces the response speed, and voltage
overshoot value becomes a little (in the direction of stability).
2.Turning it counterclockwise raises the speed and voltage shooting value becomes bigger (in the
direction of instability).
Notch position of stability adjusting volume (STAB.ADSJ) : 4/10 ※
Adjusting time constant
Instantaneous characteristic is set at the best point. So it is not necessary to adjust it. (Adjustment is
prohibited.)
The notching position of time constant adjustment volume : 1/10 ※
Protection against excessive exciting current
A circuit protector (CPR) is built-in in the power supply for prevention of AVR damage due to the
excessive exciting current caused by wrong cable connection or disconnection to detective inlet
terminal of AVR.
If this device functions, the white push button at the top of CPR is kept pressed up. In order to reset
it, push the white button on after getting rid of the cause of the excessive exciting current flow.
※:Position of notching
The top of volume resistance is marked “ arrow” at the one of the variable cross holes for
showing the set up position.