Water-wheel Generators Research Articles

Fire protection of water-wheel type generators

Fire protection of water-wheel type generators

Fire protection of water-wheel type generators

Fire protection of water-wheel type generators

The effect produced on the permeance of a laminated pole-core by the insertion of a solid steel fixing-piece

The object of the paper is to discuss the effect produced on the permeance of a laminated pole-core which has been perforated with an axial circular hole into which a solid steel fixing-piece or plug is inserted to receive the holts which attach the core to the yoke. The theory of a core in which the plug fits perfectly in the hole is first examined, and curves for the permeance calculation are prepared. The theory is then extended to apply to a plug which fits loosely in the hole, the influence of imperfect fit being shown by a numerical example.The application of the theory in practical cases is shown, in general, to be satisfactory. In the extreme example of pole-coies used in water-wheel generators, where numerous secondary matters have to be considered, the discrepancy between theory and practice is explained. The utility of the theory in calculating the permeance of transformer limbs consisting of laminae clamped together by insulated bolts is shown, and uses in certain problems of current conduction, e.g. in a perforated busbar, are suggested.

Fire Protection of Water-Wheel Type Generators

In recent years, much attention has been given to fire protection of turbo generators, resulting in a trend towards closed ventilating systems and the use of inert gas to smother combustion. Water-wheel type generators are not so well adapted to this method of protection. In water-power plants, water is the most readily available means for fire extinguishment, but its indiscriminate use through perforated pipes or nozzles may cause damage equal to that of the fire. The present paper describes a system of fire protection for water-wheel type generators which is designed to limit both fire and water damage to the section of the generator immediately adjacent to the point of origin of the fire. This is accomplished, first, by air baffles which control the flow of ventilating air around the armature end projections, and second, by the use of fusible sprinkler heads which permit the application of the water solely to the region of the fire. The means for preventing and detecting fires in such generators are also outlined. Tests made during design to establish the effectiveness of the scheme and devices used are also described.

Over-voltage on transmission systems due to dropping of load

When a water wheel-driven generator, or a hydroelectric station, loses all or a large part of its load, the voltage rises more rapidly and to a greater extent than has been generally realized. The purpose of this paper is to show the manner in which the voltage will rise under different conditions, and a method of calculating the voltage rise of a water wheel-driven generator when load is lost. The results of a large number of tests are given showing the rise in voltage on an 8500-kv-a., 6600-volt water wheel generator when load was tripped under several different conditions at three different places, namely; at the generator, on the high-voltage side of a transformer bank, and at a substation forty miles away. As it is not considered good practise to subject a transmission system to high over-voltages, consideration is given to methods of checking the voltage rise by use of relays as soon as possible after load has been dropped.

Over-Voltage on Transmission Systems Due to Dropping of Load

When a waterwheel-driven generator, or a hydroelectric station, loses all or a large part of its load, the voltage rises more rapidly and to a greater extent than has been generally realized. The purpose of this paper is to show the manner in which the voltage will rise under different conditions, and a method of calculating the voltage rise of a waterwheel-driven generator when load is lost. The results of a large number of tests are given showing the rise in voltage on an 8500-kv-a., 6600-volt waterwheel generator when load was tripped under several different conditions at three different places, namely, at the generator, on the high-voltage side of a transformer bank, and at a substation forty miles away. As it is not considered good practise to subject a transmission system to high over-voltages, consideration is given to methods of checking the voltage rise by use of relays as soon as possible after load has been dropped.

Water wheel generators and synchronous condensers for long transmission lines

Water wheel generators and synchronous condensers for long transmission lines

Waterwheel generators and synchronous condensers for long transmission lines

Waterwheel generators and synchronous condensers for long transmission lines

Waterwheel Generators and Synchronous Condensers for Long Transmission Lines

It is the intention of this paper to bring out some of the special conditions which affect the operation and design of machinery for long transmission lines and the discussion is confined largely to waterwheel generators and synchronous condensers. Under the subject of generators, the following points are discussed: Leading current drawn by transmission lines and its effect upon the stability and mechanical design of generators; characteristic curves of generators designed for operation at leading power factor; special winding connections which increase the capacity of generators for leading power factor operation for temporary periods without increasing their weight and cost; description of general construction and ventilation of a 28,000-kv-a. vertical waterwheel generator. The following points are discussion with reference to synchronous condensers: Operation at leading and lagging power factor and how it affects the stability cost and weight of the machines; special winding connections and their effect on stability; general mechanical construction with particular reference to damper winding design and the use of sheet steel end bells; the importance of losses and a curve showing values it is possible to obtain on machines with the latest improvements in design; starting kv-a. and how it may be minimized by the use of oil pressure in the bearings.

Electrical machinery tests and specifications based on modern standards

Comparisons are made of the standardization rules for electrical machinery now in force in various countries. It is shown that the differences are of a very minor character and that machinery built in conformance with the American rules will usually also conform with the rules employed in other countries. The suggestion is made that 55 degrees could be employed as the ambient temperature of reference for tropical ratings and it is maintained that such a plan fits in nicely with the value of 40 degrees already adopted as the ambient temperature of reference for other than tropical ratings. Attention is called to a series of acceptance tests on some large waterwheel generators and to the temperature results obtained by making cyclic heat runs on these machines.

Electrical Machinery Tests and Specifications based on Modern Standards

Comparisons are made of the standardization rules for electrical machinery now in force in various countries. It is shown that the differences are of a very minor character and that machinery built in conformance with the American rules will usually also conform with the rules employed in other countries. The suggestion is made that 55 degrees could be employed as the ambient temperature of reference for tropical ratings and it is maintained that such a plan fits in nicely with the value of 40 degrees already adopted as the ambient temperature of reference for other than tropical ratings. Attention is called to a series of acceptance tests on some large waterwheel generators and to the temperature results obtained by making cyclic heat runs on these machines.