Technical note Synchronous generators for steam and gas turbines Pre-engineered generators - Painting systems
ABB is a leading supplier of synchronous turbine-driven generators to power utilities, paper mills, sugar plants, oil and gas installations, and many other sectors. We have been manufacturing generators for more than 120 years and have extensive application experience with tens of thousands of installations all over the world. ABB offers reliable and efficient power generation with worldwide support.
ABB generators are designed for a long operating life in all types of environment - from clean, heated, indoor locations to open deck installations in offshore applications. AMS pre-engineered generators can be provided with two different painting systems, C3 and C5-M, to cope with different installation environments. To assure high quality corrosion protection, ABB only works with large, recognized paint suppliers and ensures that the personnel who do the painting are fully trained and competent.
Corrosivity categories ISO standard 12944-21 defines corrosivity categories according to the mass loss of unpainted steel or zinc exposed for one year at the site in question. In the absence of such figures, an estimation of the corrosivity category may be made using the table below, which is applicable to the temperate climate region. 1
ISO 12944-2, Paints and varnishes - Corrosion protection of steel structures
by protective paint systems - Part 2 Classification of environment
Corrosivity categories
Outdoor atmospheres
Indoor atmospheres
C3 Medium
Atmospheres with low salinity or moderate pollution. Urban and lightly industrialized areas. Areas with some coastal influence.
Spaces with moderate frequency of condensation and some pollution from production processes, e.g. food processing plants, breweries, diaries, laundries.
C5-M Very high (Marine atmosphere)
Atmospheres with high humidity and high salinity. Coastal and offshore splash zone areas
Spaces with almost permanent condensation and with very high salinity
ABB standard painting cycles ABB considers durability high (H) as standard for each painting cycle. The C3 painting system is the standard for AMS Basic generators.
ABB painting Pretreatment system
Environment characteristic
C3 Urban and industrial indoor and outdoor atmospheres with moderate corrosivity. Coastal areas with low salinity.
Painting3
2-component epoxy primer Acrylic topcoat Total dry film thickness
120-140 mm , 1-2 coats 40-60 mm, 1 coat 180 mm
(certain sheet metal parts)
Epoxy based powder primer 2-component epoxy primer Acrylic topcoat Total dry film thickness
60-80 mm, 1 coat 120-140 mm, 1-2 coats 40-60 mm, 1 coat 180 mm
Blast-cleaning Sa 2½ . ISO 8501
2-comp. zinc rich epoxy primer 2-component epoxy primer Acrylic topcoat Total dry film thickness
40-60 mm, 1 coat 160-220 mm, 2-3 coats 60 mm, 1 coat 320 mm
Blast-cleaning Sa 2½ . ISO 8501
Zn-phospatizing
C5-M Atmospheres with very high salinity and with almost permanent condensation. Coastal and offshore splash zone areas.
In cases where the specified color is not available, a polyurethane top coat will be used. This applies only to special colors. 3
A reduced painting system is used inside the machine
Surface treatment procedures Splatter and weld slag are removed and surface defects are repaired to preparation grade P3 according to ISO 8501-32. All steel surfaces to be painted are degreased and blast cleaned to Sa 2½ according to ISO 8501-1:19883. (A special process is utilized for powder coated parts). Edges and areas hard to reach by spraying are primed using a brush, after which primer is sprayed on all parts.
Standard top coat color is RAL 7032:
RAL 7032 The final color can be changed on specific customer request as an option. In this case the color needs to be specified with valid RAL code or NCS code in the purchase order.
When using zinc rich paint, overcoating with intermediate paint is done immediately after the minimum overcoating interval time of the paint has elapsed, in order to protect the surface from zinc corrorion products (white rust). Surface preparation and painting are carried out in indoor paint shops in a controlled environment. After the paint is cured, the parts are transported to the machine shop and assembled into the complete machine. Before application of further coats of paint, the surfaces are roughened and washed to ensure good adhesion between the paint layers. Painting is then completed. ISO 8501-3 Preparation of steel substrates before application of paints and related products - Visual assessment of surface cleanliness; Part 3 Preparation grades of welds, cut edges and other areas with surface imperfections. 3 ISO 8501-1:1988 Preparation of steel substrates before application of paints and related products - Visual assessment of surface cleanliness; Part 1 Rust grades and preparation grades of uncoated steel substrates and steel substrates after overall removal of previous coatings, also known as SS 05 59 00. 2
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Environment