Report on Test of Potter Paper Foil Oil-Filled Capacitors

The capacity and d.c. leakage of the capacitors were measured at rated voltage when dry; the capacitors were subjected to a momentary d.c. overvoltage; and the efficacy of the seal in protecting the capacity against salt water immersion was tested by measurement of the d.c. leakage after immersion in salt water. One of the capacitors which passed the test was cut open and its internal structure compared with that if a wax impregnated foil paper capacitor of the same rating. The index of refraction of the oil was measured.