The electrical measurement of steam-turbine rotor movements, with special reference to the operation and design of modern power plant

The paper shows how the increased size and higher operating steam temperatures and pressures have led to the introduction of electrical turbovisory equipment. It describes how the gear presents to the turbine operator a continuous record of the behaviour of the rotor during the whole period of starting and running on load. Experience gained with some 60 sets of equipment now in use, some of which have been in service for the past nine years, is considered in some detail. Examples are given of eccentricity and differential-expansion charts recorded in service. These relate to occasions when the turbovisory equipment indicated abnormal conditions and enabled corrective action to be taken before damage occurred. These examples are discussed in detail, and explanations of the causes of the abnormalities are suggested. The interpretation of eccentricity records is discussed, particularly with reference to the problems encountered in starting turbines. A further Section indicates how these measurements have led to a better understanding of these problems, leading in some cases to improvements in turbine design. Finally, the future trend of turbovisory equipment is considered.