No abstract

A method is described for the analysis of pressure-control systems used on large steam turbine-generator units which permits the evaluation of the performance of the system with respect to stability and response with a minimum of detailed knowledge of the system. Commonly occurring nonlinear elements are included in the analysis.

merit of bushing, 4, can be read accuratel} 7 on a vernier dial, 3 (a.), at the test station. In order to prevent tripping of the unit, while testing, a look-out switch, 8, is used to open the trip circuit and to close the test-light circuit. This switch is operated by the locking lever, 5, which must be pulled to release the testing mechanism. The switch, 8, will reset automatically when the testing mechanism is returned to neutral position. The testing mechanism is also used to measure the thrust-plate wear by comparison of test records. Initially, the testing mechanism serves to set the device in correct position. APPENDIX 4 Oil-Jet Relay Pressure Regulator Principle. The heart of the oil-jet rela}' regulator is, as its name implies, an oil jet. This oil jet originates in an ejecting nozzle from which it proceeds across the free air to the receiving nozzle which is of the same diameter as the ejecting nozzle. Ap-proximate^' in the middle, the free oil jet is influenced by a jet deflector in form of a knife edge, suspended on the pressure-sensitive element of the regulator. Fig. 14 illustrates the operation of the oil jet.

Three variables must be controlled on a double-automatic extraction turbine—speed (or power output), and the two process-header pressures—by controlling the flow of steam at different pressure levels. This has been done in a satisfactory manner on a large number of extraction turbines. However, the designs which had been developed for turbines of 50,000-kw capacity and smaller were not suitable for a turbine nearly five times as large, and a completely new control-system design had to be created.