What is MOG in Transformer?

What is MOG in Transformer?

Magnetic Oil Gauge Definition

A Magnetic Oil Gauge (MOG) is defined as a device that indicates the oil level in a transformer’s conservator tank.

Main Parts

The MOG includes a float, bevel gear arrangement, and indicating dial, essential for its operation.

Working Principle

All oil-immersed distribution and electrical transformers are provided with expansion vessel which is known as conservator of transformer. This vessel takes care of oil expansion due to temperature rise. When transformer insulating oil is expanded, the oil level in the conservator tank goes up. Again when oil volume is reduced due to fall in oil temperature, the oil level in the conservator goes down. But it is essential to maintain a minimum oil level in the conservator tank of transformer even at lowest possible temperature.

Alarm Feature

The MOG has a mercury switch that sounds an alarm when the oil level is too low, ensuring timely maintenance.

Air Cell Conservator

In air cell conservators, the float arm changes with the air cell’s size due to oil expansion and contraction, maintaining oil levels.