Ship Generator Alternator Rewinding and Servicing

The alternator is a crucial component of a ship’s generator system, responsible for generating electrical power by converting mechanical energy into electrical energy. Over time, the winding insulation of the alternator can deteriorate, leading to reduced performance and potential failures. Therefore, regular rewinding and servicing of the alternator is essential to maintain its efficiency and reliability. In this article, we will discuss the process of alternator rewinding and the key steps involved in servicing ship generator alternators.

  1. Assessment and Diagnosis:

The first step in alternator rewinding and servicing is to assess the condition of the alternator. This involves a thorough visual inspection to identify any signs of wear, damage, or overheating. The performance parameters, such as voltage, current, and frequency, should be measured to determine if there are any deviations from the manufacturer’s specifications. Additionally, insulation resistance tests should be performed to evaluate the integrity of the winding insulation. This assessment helps in diagnosing the extent of rewinding and servicing required.

  1. Dismantling and Removal:

Once the assessment is complete, the alternator needs to be dismantled and removed from the generator set. This involves disconnecting the electrical connections, removing the rotor and stator, and ensuring proper labeling of all components for reassembly. Care should be taken to follow manufacturer guidelines and safety precautions during the dismantling process.

  1. Winding Removal:

After the alternator is dismantled, the old winding needs to be removed. This is usually done by carefully cutting the wire connections and removing the windings from the stator core. Special attention should be paid to avoid damaging the stator core or any other components during this process.

  1. Core Cleaning and Inspection:

Once the winding is removed, the stator core should be thoroughly cleaned to remove any dirt, debris, or old insulation materials. A visual inspection should be conducted to check for any signs of core damage, such as cracks or corrosion. If any issues are identified, they should be addressed before proceeding with the rewinding process.

  1. Winding Rewinding:

Rewinding the alternator involves replacing the old winding with a new one. The rewinding process requires expertise and precision to ensure proper winding alignment and connections. The new winding should be carefully installed on the stator core, taking into account the specific winding pattern and insulation requirements. It is crucial to follow the manufacturer’s specifications and use high-quality insulation materials during the rewinding process.

  1. Insulation Treatment:

After the rewinding process, the insulation of the alternator windings needs to be treated to ensure its integrity and longevity. This typically involves applying varnish or resin coatings to the windings, which provide insulation and protection against moisture, heat, and contaminants. The insulation treatment should be carried out according to industry standards and the manufacturer’s recommendations.

  1. Reassembly and Testing:

Once the insulation treatment is complete, the alternator can be reassembled. This includes reinstalling the rotor and stator, reconnecting the electrical connections, and ensuring proper alignment of all components. After reassembly, the alternator should undergo comprehensive testing to validate its performance. This may include load testing, voltage and frequency measurements, insulation resistance tests, and other functional checks to ensure the alternator is operating within the specified parameters.

  1. Documentation and Maintenance:

Finally, it is important to document all the steps taken during the alternator rewinding and servicing process. This documentation should include details of the assessment, rewinding specifications, insulation treatment, test results, and any other relevant information. Additionally, a regular maintenance schedule should be established to ensure ongoing monitoring and servicing of the alternator to prevent future failures and optimize its performance.


Ship generator alternator rewinding and servicing are critical for maintaining the efficiency and reliability of the electrical power generation system on board. Through a systematic approach involving assessment, dismantling, rewinding, insulation treatment, reassembly, testing, and documentation, ship operators can ensure that their alternators are in optimal condition. Regular servicing and maintenance of alternators help to prolong their lifespan, prevent unexpected failures, and maintain a continuous and reliable power supply for the ship’s electrical systems.