The design, operation, and performance of the round hill electrostatic generator

Abstract

The design, technique of operation, and performance of the Round Hill electrostatic generator are presented in some detail. The problems of operating wide paper belts, of eliminating vibration, and of controlling humidity are discussed. The original belt charging system, with the belts operated at saturation charge density, is described and its range of usefulness is indicated. A consideration of the problems of voltage control and voltage steadiness at reduced charging currents leads to two modified designs of the belt charging system. The measurement of voltage by means of the generating voltmeter is discussed with special emphasis on the precautions necessary to eliminate or to correct for sources of systematic error. Under the conditions realizable with the Round Hill generator the probable error in voltage measurements is less than one percent on a relative scale and about two percent on an absolute scale. The magnitude of voltage fluctuations is less than 0.1 percent. The generator performance data for the positive and negative terminals are given in graphical form. The maximum charging current is 2.1 ma and is practically independent of voltage. The highest voltage obtained consistently without sparking is 2.4 megavolts positive and 2.7 megavolts negative, giving 5.1 megavolts between the terminals. At this voltage there is 1.1 ma of current available for application to an accelerating tube. © 1936 The American Physical Society.