Modular design - the basis for continous developments
All our motors are based on the modular design concept so that there is always sufficient flexibility to ensure that the starting and operation characteristics can be fully optimised for each application.
Rotor with salient poles and solid pole plates
- Ensures high thermal capacity and stability without the need for special damping winding.
- Fast control and electric stability through adaptation of the air gap, design of the pole shoes and dimensioning of the pole core.
- Solid pole shoes provide high damping without damper winding. Good overload capability and low harmonics.
- Reliable operation and long service life ensured by large cooling surfaces and effective flow of cooling air, which also results in low, uniform rotor temperature. Class H insulation of the coils gives extra thermal margins.
- Stiff rotor and minimized distance between bearings ensure low vibrations since the operating speed is well below the first critical speed.
- Over-speed tests are performed as standard. The complete rotor is balanced at operating speed.
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Stator design greatly influences stability and performance
- High-grade, low-loss electrical steel increases efficiency and reduces operating costs.
- Stiff frame transmits all forces directly to the foundation.
- The construction of the stator allows cooling with either air or water. Cooling system with combined air/water is also possible. When using water cooling the pipes are positioned in the stator slots and as well as in the stator back.
- High voltage gives low currents and reduced between the cables. This enables a simplier solution for bracing the cable ends.
- Voltage drop and short circuit current limitation are achieved by designing the stator for optimized reactance values.
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Bearings and bearing seats provide a reliable stator, rotor and shaft assembly
- Bearing housing design permits easy access for inspection and maintenance. The bearing housings are insulated from the frame to eliminate circulating currents in the shaft. The shaft can be earthed. Labyrinth seals are used to prevent oil leakage.
- Sleeve bearings are designed to be insensitive to misalignment and to permit large axial play.
- Independent lubrication system gives high reliability. Oil rings or oil reservoir ensure lubrication during emergency rundown. Hydrostatic jacking oil systems are available for applications operating at low speed.
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Exciter mounted external to the non-drive end bearing
- Simple but highly developed design having few components and well adapted protection functions offers high reliability and easy access for maintenance.
- Compact, brushless exciter unit is mounted on the rotor shaft outboard the bearing. No independent support or alignment is required.
- Improved system performance due to high field forcing possibilities. This is important when faults in the supply network arise and when increasing production of reactive power.
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