Generator Testing and Maintenance

Field Services

The following is a comprehensive list of the generator tests and inspections we perform at TGM:

On-Line Testing
- Partial Discharge Analysis
- Flux Probe Testing
Routine Off-Line Testing—Stators
- Insulation Resistance / Polarization Index
- DC Winding Resistance
- Power Factor Tip-Up and Doble Tests
- DC Step Voltage
General Inspection—Stators
- Visual Inspection
- Wedge Tightness
- EL-CID
- End Winding Resonance Test
- Capacitance Mapping Test (GE Water-Cooled Machines)
- Tube to Tube and Tube to Resistor Resistance Measurements (Westinghouse Inner Cooled Machines)
- Tube to Tube Pressure Drop Tests (Westinghouse Inner Cooled Machines)
- Stator Through-Bolt Insulation Resistance Measurements (Westinghouse Machines)
- Stator Coil Transposition Testing (Westinghouse Machines)
- AC High Potential
Routine Off-Line Testing—Rotors
- Insulation Resistance / Polarization Index
- DC Winding Resistance
- Static Turn Insulation Tests
General Inspection—Rotors
- Visual Inspection
- Pole Balance / Turn-to-Turn
- AC High Potential

Oil within the lube oil tank should be at a minimum of 130 degrees F.
Oil to the bearings should be kept at 115 degrees F (out of the lube oil coolers).
Satisfactory bearing outlet temperature (bearing oil drain) should be about 140 degrees F. Higher drain temperatures are allowable on larger units. When oil drain temperatures reach a high value such as 160 degrees, the unit needs to be closely monitored for potential bearing damage. Bearing metal temperature devices installed within the babbitt of the bearing provide a better means of monitoring the actual bearing performance.