Page 16

with simple reason such as loss of oil due to leaks, air accumulation in relay chamber which may be the absorbed air released by oil due to change in temperature etc. Rating of contacts :-

0.5 Amps. At 230 Volts AC or 220 Volts. DC.

Magnetic Oil Gauge

This is a dial type gauge, mounted directly on the conservator to indicate oil level. This is supplied with low level alarm contacts (if asked for) and the electrical connections of which are brought out to a terminal box of the oil gauge. Suitable alarm circuit may be connected to these terminals. This oil gauge is not dispatched separately, but is mounted on the conservator, with float arm adjusted to correct length.

Explosion Vent

Explosion vent is provided to give protection against the excessive pressure that may developed inside the transformer due to internal fault. On specific requirement the explosion vent is provided with two diaphragms one at the bottom (near tank) and the other at the top. If excessive pressure is developed in the tank, both diaphragms will rupture and oil in tanks will be thrown out through the vent. One pressure equalizer pipe is provided between explosion vent and the conservator to maintain equal pressure in the empty spaces of vent and conservator. In this case oil level indicator is provided on the explosion vent to indicate rupture of bottom diaphragm.