[en] Turbo-alternators are the primary producers of electric pFwer. The units in service today comprise models from post-war years of production and, to some extent, from pre-war years as well. By statistical evaluation of incidents of damage notified over the past three years, it is nevertheless possible to ascertain from the overall spectrum of these units certain focal points of damage, these being of course influenced to some degree by the trend of developments over the years. Examples of such focal points are, in the case of the stator, the windings - where mechanical influences such as electric power and electrical insulation defects are the primary cause of damage - and, in case of the inductor, the exciter windings and conductors - where grounding and winding short circuiting occurs - and also the area around the end ring and rotor end. The focal points of damage thereby ascertained are dealt with here in detail. The author goes into the physical-technical problems present in each case, showing how these were solved in the individual units concerned and what damage nevertheless occurred. Remedial measures are, where possible, elucidated and - on the basis of experience gained from the overall volume of damage - indications furnished on the consequences and/or unit risk exposure to be expected in individual cases. (orig.)

No abstract available

[en] The relationship between stiffness and sizes of the foundation arises much trouble to the designer because of the conflicting solution they require. The dynamic behavior studies of the foundations show the interest of the low fundamental frequency foundation. However, classical solutions, valuable for 3000rev/mn running speed machineries, are not suitable for large 1500 rev/mn running speed turbo-generator of nuclear power plants. A new design chosen by Electricite de France is dealt with

[en] The steady increase in the specific output was so far mainly achieved by better utilisation of the materials. Will this trend also continue in the future. The author answers this question by discussing the various limitations and the solutions suggesting themselves. (orig.)

[en] Fault transients in a.c. machines cause grid-frequency torque pulsations. For 2-pole superconducting turbogenerators in the range of rating limit a mechanical resonance frequency close to the grid frequency is expected if a screen is fixed to the inner rotor. So it must be reckoned that inadmissibly high mechanical stresses occur in the rotor construction. Therefore, in this paper the operational consequences of using a free rotating outer screen are studied. For a simplified mathematical model of the turbogenerator the nonlinear differential equations describing the behaviour are derived. In the rotating parts a random number of screens is permitted. The results of a numerical integration are presented for a three phase short circuit with subsequent voltage recovery and for a faulty synchronisation. (orig.)

[en] The facility produces a signal when the last operating turbogenerator fails, to start the reactor protection system only if the pressure at the turbogenerator outlet does not increase to a value approaching that when the turbogenerator safety valves open. Steam pressure increase above this limit following the failure of the turbogenerator signals a failure of the reactor power reduction circuits or of the steam withdrawal or relief systems. The connection allows abolishing the manual disable key of the reactor protection system or restricting its use to the period of the turbogenerator safety valve testing. Thus, operating safety improves. (J.B.)

[en] In this text we give the main innovations used in the conception of turbogenerators and alternators by GEC-Alsthom

No abstract available

[en] Modern air-cooled turbo-generators are simply constructed and thus inexpensive in comparison with hydrogen-cooled ones; in addition to this, they require little maintenance. These machines have a high degree of availability for immediate starting. The authors outline the development up to present-day machines, which are constructed for outputs of up to approx. 170 MVA. (orig.)

[en] Seismic analysis of high-speed rotating machinery such as turbo-generators and fan-motor systems are of main concern in this paper. A comprehensive review of some important studies made in this area, as well as new results of seismic response of a fan-motor system are presented here. The effects of several design parameters, namely, bearing oil-film stiffnesses and pedestal flexibilities on seismic response of high-speed rotating machinery are discussed. Important qualitative and quantitative conclusions are presented. (orig.)