Characteristics of the Arc on Contact Breaking of Noninductive Circuit in Air
1974 Volume 15 Issue 2 Pages 91-98
Details
1974 Volume 15 Issue 2 Pages 91-98
The arc on breaking of silver, tungsten and carbon contacts has been observed by means of an oscilloscope in the range of applied voltages from 20 to 110 volts and of testing currents from 0.3 to 50 amperes at both d.c. and a.c. noninductive circuits. Through the observations, length L, voltage e and current i of the arc are given by the following equations:
(Remark: Graphics omitted.)
where E is the applied voltage, I is the testing current, Em is the minimum arc voltage, Im is the minimum arc current, υ is the breaking speed, ω is the angular velocity, φ is the breaking phase angle, T is the arc duration, t is the time and K is a constant; in the case of d.c. circuit, the sin(ωt+φ) is equal to unity. These equations are applicable for the materials of both thermionic emission and field emission (T–F mechanism).
