This chapter is intended as a help in the event of an operational failure with an ABB delivered machine. The troubleshooting charts given below can aid in locating and repairing mechanical, electrical and thermal problems, and problems associated with the lubrication system. The checks and corrective actions mentioned should always be conducted by qualified personnel. If in any doubt, the After Sales of ABB should be contacted for more information or technical assistance regarding troubleshooting and maintenance.
8.1. Mechanical performance
Vibration Noise
Corrective action
x x Check lubricant quality and quantity and lubrication
system function
x x Damaged bearing parts Check bearing condition and replace bearing parts
x x Faulty bearing assembly Open and readjust the bearing
x x Faulty cooling fan(s) Imbalanced or damaged
fan(s) Check and repair cooling fan(s)
x Inspect and repair cooling system
x Inspect and repair excitation system
x x Check machine alignment
x x Rebalance rotor
x x Check rotor wedges, poles etcx, repair and rebalance
rotor
x x Check the balance of connected machinery and
coupling type
x x Check alignment and coupling function and type
x x Check coupling function
x Reinforce foundation as per ABB instructions
x Check main machine and excitation machine windings
x x Check that network balance fulfils requirements
x x Check bearing pedestal alignment
x Check and clean machine interior, dry windings
x x Measure and adjust airgap
Malfunctioning excitation system
Mechanical performance
Troubleshooting
Lubrication malfunction
Malfunctioning cooling system Bearing malfunction
Experienced malfunction
Possible cause
Machine misalignment Rotor or shaft imbalance Loose parts in rotor
Vibration coming from connected machinery Axial load coming from connected machinery Faulty or incorrectly assembled coupling Insufficient foundation strength
Main machine or excitation machine winding fault Excessive network unbalance
Bearing misalignment
Foreign material, moisture or dirt inside the machine Airgap not uniform
8.2. Lubrication system and bearings
8.2.1. Lubrication system and sleeve bearings
High bearing temperature
Oil leaks
Oil inside the machine
Bearing noise or vibration Visibly poor oil quality Corrective action
x x x Oil flow malfunction Check oil pump, oil reduction valve and oil filter
x Oil viscosity too high Check oil temperature and oil type
x x x x Check ABB oil recommendations
x Check lubrication system and adjust oil temperature
x x Oil quality is reduced Incorrect oil change period Clean bearing and change oil x x x x Excessive axial load Faulty coupling or mounting Check coupling, mounting and alignment
x x x Realign machine
x x Verify correct bearing assemblage and adjustments
x x x Oil impurities Change oil, check bearing condition, replace bearing
shells
x x Bearing currents Restore bearing insulation, replace bearing shells
x x Complete bearing failure Replace bearing parts
x x Normal wearing Replace bearing shells
x x Operating speed too low Check the operating speed range of bearing x Faulty instrumentation Faulty temperature detector Check bearing temperature measurement system
x Replace bearing seals
x Oil flow too high Faulty regulator settings Check and correct oil flow x Problem in oil return flow Faulty oil piping Check oil return pipe inclination
x External vacuum Rotating equipment nearby Check pressure levels, relocate rotating equipment x x Internal over pressure Pressure compensation failure Remove cause for internal over pressure
x Replace or repair machine seal
x Check pipeline connections and oil filter tightness
x x Clean bearing and check seal condition
Damaged or worn-out bearing seals
Damaged machine seal
Faulty assembled or maintained lubrication piping Foreign matter inside the bearing
Troubleshooting
Unsuitable oil quality Oil inlet temperature too high
Machine misalignment
Lubrication system and sleeve bearings with oil supply
Damaged bearing shells
Experienced malfunction
Possible cause
Insufficient lubrication
Incorrectly assembled bearing
8.3. Thermal performance
8.3.1. Thermal performance, air-to-water cooling system
High winding temperature High cooling air temperature Water leakage
alarm
Corrective action
x x Damaged cooling fan Replace fan
x x Fan rotating in wrong direction Change shaft mounted fan or correct external blower
motor operation
x x Dirty machine interior Clean machine parts and air gaps
x x Coolant pipes are blocked Open cooler and clean pipes
x x Faulty coolant pump Check and repair the pump
x x Faulty flow regulator settings Check and adjust coolant flow
x x x Leaking cooler header Replace the cooler header
x x Air inside the cooler Bleed the cooler through bleeder screw
x x Emergency cooling hatch open Close emergency cooling hatch tightly
x x Adjust cooling water temperature
x Overload Control system setting Check machine controls, eliminate overload
x Check that network balance fulfils requirements
x x x Check measurements, sensors and wiring
x Let the machine cool down before restarting
x Check main machine and excitation machine windings
Cooling water inlet temperature too high
Troubleshooting
Thermal performance, air-to-water cooling system
Main machine or excitation machine winding fault
Experienced malfunction Possible cause Low primary cooling circuit performance Low secondary cooling circuit performance
Faulty instrumentation or measurement system Too many starts
Network unbalance
For high bearing temperature, see Table 8.2, Lubrication system and bearings. NOTE:
8.4. Electrical performance
8.4.1. Electrical performance and excitation system of generators
Lost excitation
Increase in excitation current Malfunction during start-up
Performance deviation Operation not adjustable Faulty parallel operation
Corrective action
x x Abnormal speed Faulty speed control Check speed control of operating machine
x x Check that network balance fulfils requirements
x Check speed control of operating machine
x x Faulty settings Check excitation panel relay and voltage regulator setting x x Faulty wiring Check excitation panel control cubicle and generator x x Demagnetised excitation magnet See main connection diagram to restore permanent magnet
excitation
x x x x Check transformer winding insulation resistance and connections x x x x x Check transformer winding insulation resistance and connections
x x Check transformer winding insulation resistance and connections
x x Check operation of short circuit excitation system
x Check main machine winding and insulation resistances
x x Check exciter winding and insulation resistances
x x x x x Check connection and condition of rectifier components
x x x x Check electrical connections in excitation system
x x Excitation
equipment fault Excitation panel equipment Check and replace excitation panel equipment
x x x x x x Check and adjust voltage regulator settings
x Bad AVR tuning
parameters Voltage oscillation, poor response Check AVR tuning (PID parameters)
x x x x x x Check and replace voltage regulator
x x x x x x Check AVR wiring and connections
x Check AVR condition
x x x Check connections and condition of voltage reference
x x Check actual value measurement system and electrical
connections
Troubleshooting
Network phase unbalance Speed variation of operating machine
Defective voltage transformer
Electrical performance and excitation system of generators with transformer excitation
Experienced malfunction
Possible Cause
Field application failure
Defective parallel operation transformer Defective current transformer Short circuit excitation system failure Main generator winding fault Excitation system winding fault Faulty rotating rectifier Faulty wiring in excitation system Faulty AVR settings
No actual value information for AVR Defective AVR
Faulty AVR wiring or incorrect connections Power factor variation over permitted values Faulty external voltage reference system