CBM of Generators

Generator means Turbine- Alternator (TG) Set or Diesel -Alternator DG set. Alternator is important part of any electricity generating set and mostly not maintained. All the attention of maintenance team is grabbed by the prime mover Engine or Turbine & the alternator remains cornered.   

The protection of alternator is always SPDP- Screen Proof Drip Proof. Hence, there are chances of failure of alternator windings during rainy season. 

The major components those fail in alternator are Windings – Main Armature, Main Field, Exciter Armature, Exciter field, Automatic Voltage Regulator (AVR), RRA Assembly (Diodes/ Thyristors), Bearings, Bearing Housings, Shaft, Couplings etc.

The Condition Monitoring of generator/ Alternator (Generator Condition Monitoring) includes, techniques like Vibration Measurements, Ultrasound Measurements, Thermography, No Load Excitation Current & No Load Voltage Measurements, Load Current & Excitation Current Measurement & Vibration Probing Study etc.

CBM of Alternator = CAss of Alternator + Vibration Probing Study + Corrective Actions + CM of Alternator – Trend Analysis + RCSA + CAPA

The CBM or Predictive Maintenance of Alternator may include,

1. Acoustic Greasing of both the bearings and
2. Overhauling of all the four windings (Yearly).

If we include Acoustic Greasing & Overhauling in CBM of Alternator, then,

CBM of Alternator = CAss of Alternator + Vibration Probing Study + Overhauling + CM – trend + Acoustic Greasing + RCSA + CAPA

It is more cheaper to maintain the condition of alternator then the cost of rewinding. Many times the stator core or rotor core gets failed due to rubbing of stator-rotor and then the cost of restoring the parts goes to ceiling. It is advisable to consider alternator under Predictive Maintenance or under CBM.