PURPOSE: To obtain a sufficient tracking resistance characteristic even in an actual equipment shape, by applying a prescribed voltage across both end electrodes to be tested in a tank for an electrolyte, and varying the level of an electrode liquid.
CONSTITUTION: A body 3 corresponding to an actual equipment is suspended fixedly in the tank 6 by a suspending device 1 so that electrodes 4a and 4b are at a higher and a lower position respectively. In this state, a prescribed voltage is applied between the electrodes 4a and 4b by a electric feeding device 20 and the electrolyte 5 is supplied into the tank 6 by a pump 7. This supply is continued until the liquid level 10 of the liquid 5 contacts the electrode 4a by an upper limit switch 8. Then, the liquid 5 is discharged out of the tank by the pump 7 and when the level 10 reaches the electrode 4b, the pump 7 is stopped through a lower-limit switch 9. This state is held until discharging is not generated on the surface of the body 3 any more. This operation is repeated until an electricity conduction path is formed in the body 3 and a current regarded as the destructive current flows. The tracking resistance characteristic of the body 3 is evaluated from the frequency of the repetition.
SATOU KENICHI
TSUSHIMA MASAMITSU
