We have a catalog of services for reconstruction, rehabilitation, maintenance, repair,
repowering and modernization of these equipment.
As insulating materials have been developed, with better dielectric properties, it has become possible to reduce the wall thickness of the insulation. Thus, in old generators to which it is desired to change windings, it is possible to increase the section of the copper conductor and achieve an increase in power or a reduction in temperature.
Rehabilitation of winding fastening systems, including: cleaning; change of wedges, spacers, moorings and clamping rings; removal, evaluation, replacement, rearrangement and assembly of coils in stators windings; application of paints and ribbons of semiconductor material to rehabilitate electric field graduation systems; change of insulation and, if necessary, coils and field windings in smooth and outgoing pole rotors; minor surface repairs on stator cores; and modification of insulation design to increase efficiency and, if possible, generator power.
In case of major damage in stator cores, GENERMEX offers the supply and installation of lamination packages or complete cores, to replace packages or cores damaged by electrical or mechanical faults. This includes internal laminations, external laminations with welded “I” bars, oppressor fingers, pressure plates and any other component that is necessary to recover or improve the conditions of clamping, tightening and original magnetic characteristics of the core.
In plain-pole rotors, GENERMEX offers the removal and placement of retaining rings (bells), the cleaning and surface rehabilitation of coil heads, the replacement of spacers, and in the event that the retaining rings are damaged or in case of required by our client, GENERMEX offers the supply and installation of retaining rings, fans and couplings or special parts of the rotor.
In outgoing pole rotors, GENERMEX offers poles reisolation and fabrication and, if necessary, supply of “V” pole coil separator blocks.
In both types of rotors, GENERMEX offers the execution of electrical, mechanical, non-destructive tests to the exposed parts of the rotor, as well as the execution of minor works such as polishing of rubbing rings and trunnions, rectification of lubrication labyrinths or seal, and the replacement of components such as slip rings, diodes, power lines to the field and dynamic rolling at low speed.
The rewind of generator stators consists of the removal of the exhausted or failed winding and the installation of a new winding. The design of the new coils includes the application of new materials in such a way that, if the original design allows it, the generator has greater capacity or works colder and thus extends its life expectancy.
Before installing the new winding the state of the interlaminar insulation of the stator core and the tightening torque of the clamping systems of the laminate are qualified. It is not advisable to install a new winding, whose life expectancy exceeds 30 years, in a core whose life expectancy is lower.
The rewind includes the analysis and implementation, change of wedges, flat and corrugated fillings, separators, rings and all the assembly materials, using the most modern. Particular attention is paid to ensure that no part of the coils or connections can vibrate and wear out the insulation or electric field relief and graduation structures.
Of all the techniques used to determine the condition of a rotary electric machine, none is as revealing as a thorough visual inspection by experienced personnel. GENERMEX has extensive experience and specialized human resources to perform visual inspections in generators.
To diagnose the state of parts and assemblies of a generator, it is necessary to complement the visual observations and the operating experiences, with results of the following electrical and mechanical tests, offered by GENERMEX.
The test known as “ELCID” (Electromagnetic Core Imperfection Detection) allows us to evaluate the interlaminar insulation status of the stator core. This test uses little energy and is very effective.
If necessary, it is possible to perform a test that requires high energy and is known as Toroid.
The results of tests allow us to know the state in which the isolations are in stator, rotor and core coils; semiconductor structures that relieve and graduate electric field efforts; the systems of subjection of the windings that avoid their vibration and wear; ventilation and cooling systems; electrical connections and contacts; and the laminations of the electromagnetic cores, among other generator components.
With these results we can decide if a generator is in safe and reliable operating conditions.
GENERMEX, offers a Course on Electric Power Generators, oriented towards the maintenance of these equipment. The Course is divided into Modules, each of which can be taught in one or more sessions, depending on the needs and possibilities of the interested staff.
This course seeks to identify and assimilate the technological knowledge associated with the generators that our clients operate and maintain. This to help them improve their continuity, reliability, safety and cost indexes.
The content of the Course can be synthesized in four areas of expertise:
We have our product catalog.
Using the most modern manufacturing materials and systems, GENERMEX manufactures half coils, also called rods or Roebel rods. This type of construction is characterized by having the conductors short-circuited at their ends and transposed in part or along their entire length. Each conductor is covered with layers of dacron and fiberglass.
The main insulation is Class “F” and is constructed from layers of mica tape with epoxy resin. In their straight part, the coils are covered with semiconductor tape, to avoid partial discharges to the slot. At their ends, the coils are covered with a potential graduation tape, to avoid superficial discharges at the exit of the core.
GENERMEX manufactures complete coils of one or more turns, known as Diamond, with Class “F” insulation, for electric generators with nominal voltages of up to 20 KV, processed unitarily, in presses that apply heat and pressure cycles, necessary to obtain a homogeneous insulation system, with the same proportion of mica and resin in all its parts, and thus obtain the levels of partial discharges and power factor of the insulation, which distinguish the quality of our coils, and that allow us to meet the specifications and tests more demanding, required by our customers.
Each coil is assigned a number and Electrical Tests are applied to it:
Using fiberglass laminates, with defined shape and prestressing, we offer the manufacture of the following parts and components:
For finishes and specific work that our customers do, we offer the following insulating materials:
GENERMEX maintains an inventory of forges covering a wide range of measurements in order to supply rings for any turbogenerator.
Turbogenerator field coils are subject to high centrifugal forces and must be well secured to avoid catastrophic failures. Its sides are housed in grooves of the rotor shaft and are attached by metal wedges. Their heads are housed in the ends of the axis of the rotor, separated from each other by blocks of insulating material and the assembly is held by rings. These retaining rings are manufactured from forged steel alloy specified by the ASTM standard to 289 “alloy steel forgings for non magnetic retaining rings for generators”.
Due to its composition, this material is known as 18Cr / 18Mn steel.
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