From Current Literature1

Air-Jet Rectifier for High-Voltage Alternating Currents

(Wolcott and Ericson. An Air-Blast Rectifier of High Tension Alternating Currents. The Physical Review, p. 480, June 1917).

Wolcott and Ericson, in the laboratory of the Western Precipitation Company (California), showed that the rectifying action of the system consisting of a disk and a point, used in induction X-ray installations for the elimination of reverse currents, can be considerably improved by the application of an air jet according to the following scheme (Fig. 1). \(T\)—high-voltage transformer from 25 to 350 kilovolt; \(P\)—metal disk 10 cm in diameter; \(B\)—a tube, either metallic or made of an insulator, with an opening \(O\) of 4 mm diameter, from which protrudes a point 1.5 mm in diameter; \(L\)—distance between the point and the opening, 9.5 cm; \(D\)—distance between the disk and the point, 1.76 cm; \(M\)—direct-current ammeter. Air under pressure enters the side tube \(A\)

Fig. 1.

at 6 cm; \(R\)—the water resistance. The tip may be placed either inside the tube \(B\), or in the opening \(O\), or outside the tube. In the first two cases the tube \(B\) must be made of an insulator (glass), with electrodes of aluminum; in the last case the tube \(B\) is metallic and the electrodes are copper or iron. The rectifying action depends on the pressure of the air jet, the mutual position of the electrodes, and the diameter of the opening \(O\). When the pressure is increased from zero to a certain value, a maximum of the rectifying action is observed, after which it begins to fall.

Fig. 2.

Alternating currents were investigated with frequencies from 50 to 500 per sec. and strengths up to 100 milliamperes. The curves (Fig. 2), obtained with an oscillograph without an air jet (1), and with the jet (2), show the result of applying a gas jet for rectifying the current.

N. Selyakov.

1. Most of the works in this section were reported at the Physical Colloquium of the Scientific Institute. ↩