MOG (Magnetic Oil Gauge) in transformer-Working and Construction

Magnetic Oil Gauge is also referred as MOG. it is a device that is fitted on the conservator tank to monitor the transformer oil level. 

 

The MOG is a small circular dial shape window placed on the side of the conservator tank with a float mechanism inside the conservator that rises and falls with the oil level

 

MOG is used to indicate the level of transformer oil inside the tank. 

 

Transformer oil plays an important role in the reliability of transformers. it acts as insulation between the tank and the winding. 

Oil also provides cooling to the transformer core and winding. if the oil level fall below the desired level there is a chance of winding overheating. 

 

The MOG is a simple yet effective device that helps to monitor the oil level inside the tank and gives an alarm in case the oil level becomes low.

In this article, we will discuss the Construction of MOG, its working principle, its importance, maintenance, and installation.

Construction of MOG or Magnetic Oil Gauge

Construction of MOG is simple, it consists of a float, Bevel gear arrangement, and indication dial. 

The indication dial has a scale from empty-fill level to Full. Some MOGs indication dial has a scale of 1/4, 1/2, and 3/4 to show the oil level. 

In some cases prescribed oil levels at either 30°C or 35°C ambient temperature may also be shown on the MOG dial. 

The Mercury switch and bevel float are attached to the pointer of the magnetic oil gauge. 

When the pointer deflects due to a change in the oil level inside the tank, the mercury switch attached to it also rotates. And it gives an alarm when the oil level falls to the fill level.

MOG is installed on the conservator tank at a 15 or 30-degree angle for the best view of the dial. And sometimes placed at 0 degrees. As shown in the below diagram. 

Working Principle of MOG

The MOG is a vertical dial-shaped device installed on the conservator tank of the transformer. 

The oil level shown by the MOG is the same as that inside the transformer tank. 

As the oil level may rise due to increased load or any fault and fall because of a decrease in the surrounding temperature. 

The rise and fall of transformer oil can be observed from outside with the help of a Magnetic Oil Gauge. 

As the change in oil level occurs it deflects the pointer on the dial gauge of MOG to indicate an increased or decreased oil level. 

Importance of Magnetic Oil Gauge:

The Magnetic Oil Gauge is a crucial component of an electrical transformer as it helps to monitor the oil level inside the transformer tank. 

A low oil level can lead to overheating of the transformer core and winding, which can cause a catastrophic failure of the transformer. 

On the other hand, an excess oil level can result in oil spills, which can be dangerous and polluting. 

The MOG is important to indicate oil inside the tank and maintain it within safe limits, thereby preventing damage to the transformer and ensuring its reliability.

Maintenance of MOG:

The MOG requires regular maintenance to ensure its proper functioning. The glass dial should be kept clean and free from dust and dirt. 

Conclusion:

In conclusion, the MOG is an essential component of an electrical transformer. It helps to monitor the oil level inside the transformer tank, which is crucial for the proper functioning of the transformer. The MOG requires regular maintenance to ensure its proper functioning, and any defects or damages should be repaired or replaced immediately. By keeping the Magnetic Oil Gauge in good condition, transformer operators can ensure the safe and reliable operation of their transformers.

Frequently asked questions

What is a Magnetic Oil Gauge in a transformer?

Magnetic Oil Gauge is a device used in transformers to monitor the level of transformer oil in the tank.

What does MOG in transformer stand for in Transformers?

MOG stands for Magnetic Oil Gauge

What is the purpose of a MOG in a transformer?

The purpose of a MOG in a transformer is to monitor the level of transformer oil in the tank.

Why is it important to monitor the oil level in a transformer?

It is important to monitor the oil level in a transformer because the oil is used for both the insulation and cooling of the transformer. If the oil level is too low, it can cause the transformer to overheat and be damaged.

How to read the transformer oil level gauge?

Mog dial has a scale of 1/4, 1/2, and 3/4 which reflect the oil level in the conservator tank. Some mog has dial marked with Empty, Fill Level to Full level from that we can read transformer oil level.