PI Manufacturing AC generators - Manual (Page 27)

7.4.2 SX440 AVR - FAULT FINDING
No voltage
build-up when
starting set
1. Check link K1-K2 on auxiliary
terminals.
2. Check speed
3. Check residual voltage. Refer to
subsection 7.4.7.
4. Follow Separate Excitation Test
Procedure to check generator and
AVR. Refer to subsection 7.5.
Unstable voltage
either on no-load
or with load
1. Check speed stability.
2. Check stability setting. Refer to
subsection 4.6.
High voltage
either on no-load
or with load
1. Check speed.
2. Check that generator load is not
capacitive (leading power factor).
Low voltage
no-load
1. Check speed.
2. Check link 1-2 or external hand
trimmer leads for continuity.
Low voltage
on-load
1. Check speed.
2. Check UFRO setting. Refer to
subsection 4.7.1.1.
3. Follow Separate Excitation
Procedure to check generator and
AVR. Refer to subsection 7.5.
7.4.3 SX421 AVR - FAULT FINDING
No voltage
build-up when
starting set
1. Check circuit breaker ON. Refer to
subsection 6.4.1.
2. Check speed
3. Check residual voltage. Refer to
subsection 7.4.7.
4. Follow Separate Excitation Test
Procedure to check generator and
AVR. Refer to subsection 7.5.
Unstable voltage
either on no-load
or with load
1. Check speed stability.
2. Check stability setting. Refer to
subsection 4.6.
High voltage
either on no-load
or with load
1. Check speed.
2. Check link 1-2 or external hand
trimmers leads for continuity. Check
continuity of leads 7-8 and P3-P2 for
continuity.
3. Check that generator load is not
capacitive (leading power factor).
Low voltage
no-load
1. Check speed.
2. Check link 1-2 or external hand
trimmer leads for continuity.
Low voltage
on-load
1. Check speed.
2. Check UFRO setting. Refer to
subsection 4.7.1.1.
3. Follow Separate Excitation
Procedure to check generator and
AVR. Refer to subsection 7.5.
Excessive
voltage/speed
dip on load
switching
1. Check governor response.
2. Refer to generating set manual.
Check ‘DIP’ setting. Refer to
subsection 4.7.1.4.
7.4.4 TRANSFORMER CONTROL - FAULT FINDING
No voltage
build-up when
starting set
1. Check transformers rectifiers.
2. Check transformer secondary
winding for open circuit.
Low voltage
1. Check speed.
2. Check transformer air gap setting.
Refer to subsection 4.7.2.
High voltage
1. Check speed.
2. Check transformer air gap setting.
Refer to subsection 4.7.2.
3. Check transformer secondary
winding for open circuit.
Excessive
voltage/speed
dip on load
switching
1. Check speed drop on-load.
2. Check
transformers rectifiers.
3. Check transformer air gap setting.
Refer to subsection 4.7.2.