Magnetic Amplifier Controls for Rectifier Protecting Underground Metallic Structures Cathodically. By Oliver Henderson. CORROSION, Vol. 9, No. 7, 216-220 (1953) July.
Discussion by Daniel R. Werner, American Telephone and Telegraph Co., Kansas City, Mo.
Mr. Henderson indicates in his paper that the amplifier was designed to give a power amplification of 12,000. The power to activate the amplifier is obtained from the changes in the potential between the cable and the waterpipe. These changes in potential are caused by changes in the load on the electric railway system and these changes occur at various rates. It is indicated that a potential change of 0.2 volt cable-to-waterpipe (the waterpipe-to-earth potential variation is small as compared to the cable-to-earth potential variation) is sufficient to swing the amplifier from its minimum output to its maximum output.
Magnetic amplifiers do not have an instantaneous response time as far as the input and output is...
