PI Manufacturing AC generators - Manual (Page 28)

7.4.5 MX341 AVR - FAULT FINDING
No voltage
build-up when
starting set
1. Check link K1-K2 on auxiliary
terminals
2. Follow Separate Excitation Test
Procedure to check machine and
AVR. Refer to subsection 7.5.
Loss of voltage
when set runninig
1. First stop and restart set. If no
voltage or voltage collapses after
short time, follow Separate Excitation
Test Procedure. Refer to subsection
7.5.
Generator
voltage high
followed by
collapse
1. Check sensing leads to AVR.
2. Refer to Separate Excitation Test
Procedure. Refer to subsection 7.5.
Voltage unstable,
either on no-load
or with load
1. Check speed stability.
2. Check “STAB” setting. Refer to Load
Testing section for procedure. Refer
to subsection 4.6.
Low voltage
on-load
1. Check speed.
2. If correct check “UFRO” setting.
Refer to subsection 4.7.1.1.
Excessive
voltage/speed
dip on load
switching
1. Check governor response. Refer to
generating set manual. Check “DIP”
setting. Refer to subsection 4.7.1.4.
Sluggish
recovery on load
switching
1. Check governor response. Refer to
generating set manual.
7.4.6 MX321 AVR - FAULT FINDING
No voltage
build-up when
starting set
1. Check link K1-K2 on auxiliary
terminals. Follow Separate Excitation
Test Procedure to check machine
and AVR. Refer to subsection 7.5.
Voltage very slow
to build up
1. Check setting of ramp potentiometer.
Refer to 4.7.1.5.
Loss of voltage
when set running
1. First stop and restart set. If no
voltage or voltage collapses after
short time, follow Separate Excitation
Test Procedure. Refer to subsection
7.5.
Generator
voltage high
followed by
collapse
1. Check sensing leads to AVR.
2. Refer to Separate Excitation Test
Procedure. Refer to subsection 7.5.
Voltage unstable,
either on no-load
or with load
1. Check speed stability.
2. Check “STAB” setting. Refer to Load
Testing section for procedure. Refer
to subsection 4.6.
Low voltage
on-load
1. Check speed.
2. If correct check “UFRO” setting.
Refer to subsection 4.7.1.1.
Excessive
voltage/speed dip
on load switching
1. Check governor response. Refer to
generating set manual. Check “DIP”
setting. Refer to subsection 4.7.1.4.
Sluggish
recovery on load
switching
1. Check governor response. Refer to
generating set manual. Check
“DWELL” setting. Refer to Load
Testing section 4.7.1.4.