27
Continued
Maintenance or Test
Recommended Interval
Stator winding - wedge tightness
measurements
measurements
During 1-, 2½-, and 5-year warranty inspections;
thereafter, performed after rotor is removed
(particularly if unit in operation for 20-25 years
without rewedging).
thereafter, performed after rotor is removed
(particularly if unit in operation for 20-25 years
without rewedging).
Stator winding - power factor measurements
(Doble)
(Doble)
Nonroutine. May be performed in conjunction
with other generator-condition tests.
with other generator-condition tests.
Stator core - physical inspection
During 1-, 2½-, and 5-year warranty inspections;
thereafter, during major maintenance outages
but not to exceed 5 years.
thereafter, during major maintenance outages
but not to exceed 5 years.
Stator core - core magnetizing test
Nonroutine. Should be performed prior to rewind
or if core has been damaged.
or if core has been damaged.
Rotor - physical inspection
During major maintenance outages but not to
exceed 5 years.
exceed 5 years.
Rotor - insulation resistance polarization
(
(
megohmmeter)
Annually or after maintenance outage.
Rotor - AC pole drop test
Nonroutine. Performed when deterioration is
suspected.
suspected.
Thrust and upper guide bearing insulation test
Annually per FIST Volume 5-11.
Governors control generator power and frequency output by regulating water flow to
the turbine. Governors may be mechanical type or electrohydraulic type having
electronic controls. New digital governors substitute digital control circuits for analog
electronic controls of older electrohydraulic governors.
the turbine. Governors may be mechanical type or electrohydraulic type having
electronic controls. New digital governors substitute digital control circuits for analog
electronic controls of older electrohydraulic governors.
Mechanical governor maintenance is fully described in FIST Volume 2-3,
Mechanical
Governors for Hydraulic Units. Mechanical maintenance requirements for all types of
governors is identified in FIST Volume 4-1A, Maintenance Scheduling for Mechanical
Equipment. The electrical maintenance schedule below supplements these mechanical
maintenance requirements.
Governors for Hydraulic Units. Mechanical maintenance requirements for all types of
governors is identified in FIST Volume 4-1A, Maintenance Scheduling for Mechanical
Equipment. The electrical maintenance schedule below supplements these mechanical
maintenance requirements.