Generator Rotor Modernizations

Modernizing your generator rotor can help increase the availability of your plant and facilitate adaptation to current grid requirements. The individual operation and maintenance history of your rotor is analyzed by our experts in order to determine the recommended modernization measures.

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Our Rotor Modernization Concepts in Detail

Rotor Rewind

Siemens offers various scenarios for implementing a rewind as the objective of any modification is to minimize standstill times. A rotor rewind always involves the replacement of the winding, including the entire winding insulation and spacers, and thus can “reset” the “service life clock” for the insulation system.


We offer four basic concepts for rotor rewinding.

According to your generators configuration, further customized rotor modernizations can be offered by Siemens.

Seed Rotor Concept

In this scenario, you receive a rewound and requalified rotor in exchange for your previous rotor at the start of the overhaul. Compared to a new rotor, a requalified rotor may be the more cost-effective and faster to implement alternative.

 

With this scenario the total duration of an overhaul can also be reduced up to one-third in comparison to a standard rewind. However, a prerequisite is that a rotor of the same type is available at Siemens.

 

As an original equipment manufacturer, we have access to all original drawings, specifications, engineering calculations and manufacturing records for your Siemens generator and can therefore maximize complete electrical and mechanical interchangeability.

According to your generators configuration, further customized rotor modernizations can be offered by Siemens.

Replacement Rotors

Siemens can offer a newly fabricated replacement rotor, which is supplied directly to the power plant after manufacturing.  This case can minimize standstill time for installation as the new rotor can be available immediately after removal of the old rotor. Optionally, the removed rotor could be refurbished by rewinding and would then be available as your own spare rotor. We can offer a long term storage and transport container for storage of this rewound spare rotor on the premises of the power plant.

 

This scenario is especially interesting for customers with several generators of the same type and/or very high demands on the availability of their units. The higher cost for the acquisition of a new rotor can quickly pay off through maximum availability and, if the optional spare rotor is selected, through increased flexibility in the event of potential future generator issues.

According to your generators configuration, further customized rotor modernizations can be offered by Siemens.

Retaining Ring Replacement

In general, retaining rings are considered amongst the highest stressed components in turbogenerators. As a result of fatigue from torsional forces induced by electrical grid system disturbances in the vicinity of the power plant, retaining ring cracks can occur.

 

A periodic inspection of retaining rings and a qualified non-destructive examination procedure are recommended on all generator rotors. This inspection is intended to evaluate the structural integrity of non-magnetic retaining rings and insert rings.

 

In case of findings, and to help avoid potential system downtime and costly repairs while increasing reliability and availability, replacement of retaining rings or insert rings are recommended and can be offered by Siemens.


Multiple envelope 18Mn-18Cr1 retaining ring forgings have been procured to support necessary replacements of other original equipment manufacturers units.

According to your generators configuration, further customized rotor modernizations can be offered by Siemens.

Rotor Reliability & Availability Improvement Package

In order to enable plant operation with enhancements related to start/stop cycles and overall rotor reliability and availability, Siemens offers technical improvements for generator rotors. Based on the individual operation and maintenance history of your rotor, we can offer modernization solutions including the following engineered components:

According to your generators configuration, further customized rotor modernizations can be offered by Siemens.

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Getting in touch

If you have any questions or would like to find out how we can help you to modernize your generator equipment, please let us know.