Transformer reliability is determined by various aspects, such as the insulation, temperature management, and the right transformer oil level. The transformer oil plays an important role in terms of insulation and cooling; hence, keeping track of the oil level is very crucial for safe and reliable operations of transformers. The magnetic oil gauge is an easy way through which the transformer operator can keep track of the oil level of the transformer conservator without having to come into physical contact with the oil.
For those who operate the transformer, maintenance staff, and electrical equipment operators, knowledge of how the magnetic oil gauge operates and installation procedures is vital in avoiding any operational problems that may arise.
What is a Magnetic Oil Gauge?
Magnetic oil gauge is another name for the MOG. This is a device whose aim is to indicate the oil level in the transformer conservator.
As the level of oil in the transformer fluctuates, the float rises and falls. The magnet, which is attached to the float, transmits this movement to the exterior indicating system, ensuring that the level of oil is monitored through a reading on the indicator without the need for a direct mechanical link.
This is very handy in cases of oil-filled transformers where constant oil level observation is required.
How Does a Magnetic Oil Level Gauge Function?
The working principle of a magnetic oil level gauge is fairly easy to understand.
In the conservator, the float rises and falls in accordance with the level of oil in the transformer. This results in the rotation of the magnet attached to the float. The movement of the magnet is conveyed to the exterior indicator via magnetic coupling, moving the pointer of the gauge to correspond with the level of oil.
This occurs in four stages:
Oil level changes: Transformer oil is capable of expanding and contracting due to operating conditions and temperatures.
Float changes: The float that is installed in the conservator will rise or fall depending on the oil level.
Magnetic changes: The magnetic device is sensitive to the float movements.
Pointer changes: The changes are reflected on the pointer, indicating the oil level on the dial.
The indication mechanism does not need a mechanical link from the oil to the indicator dial via the tank wall, making it easy to control externally.
There are some magnetic oil gauges that also have switching arrangements. For instance, MOG SO-4 provided by Dhruti Sales has a 100 mm dial and 1 NO switching arrangement with Low Oil Level Alarm (LOLA).
Why Is a Magnetic Oil Gauge Important for Transformers?
Transformer oil is used for insulation and heat dissipation of transformers. Therefore, any substantial decrease in the oil level might negatively influence transformer operation and also might mean leakage or other operating issues.
With the magnetic oil gauge, maintenance staff will be able to identify oil level changes in the course of inspections. Thus, teams will be able to investigate problems before they become serious issues.
This feature is especially helpful where the transformers are fitted in industrial plants, substations, power distribution systems and other electrical systems where equipment reliability is critical.
Factors to Consider When Installing a Magnetic Oil Gauge
Proper installation is necessary to get accurate oil level readings. Prior to the installation of a magnetic oil gauge, the specifications of the gauge need to match the conservator type and mounting considerations of the transformer.
1. Matching the Gauge with the Type of Conservator
The type of gauge to be used should be appropriate for the type of transformer conservator. There are various types of MOG at Dhruti Sales and some can be mounted on air cell type conservators such as the MOG SO-6 ATMS and MOG SO-10 ATMS.
2. Selection of the Right Dial Size
The next factor is the dial size of the gauge.
There are different sizes in the line up. The MOG SO-4 comes with a 100 mm diameter dial, MOG SO-6 ATMS has a 150 mm dial, whereas the MOG SO-10 ATMS has a 250 mm dial.
3. Check Mounting and Connection Specifications
It is important to check the gauge mounting specifications, dimensions and available space at the conservator before installation. The gauge must be properly installed and set up so that its readings are clear during inspection.
4. Confirm the Gauge Indication
The indication from the gauge after installation should be checked against the true reading for the expected oil level and installation specifications. Unusual movement of the pointer or indications should be checked out before normal service of the transformer.
Maintenance of the Magnetic Oil Gauge
The magnetic oil gauge is manufactured for reliable service but it is still important to inspect the device regularly. Maintenance teams need to inspect the gauge during transformer maintenance.
Inspect the Pointer and Dial
Ensure that the pointer moves freely and that the dials are readable. The sticking of the pointer is a sign that the gauge has some internal or magnetic malfunction.
Check for Oil Leakage
Oil leakage at the point of mounting and connections should be noted. Oil leakage is serious because it reduces the available oil level.
Functionality Check of Alarm Switch
In cases where the magnetic oil gauge has an alarm switch fitted, its performance shall be checked following the manufacturer’s recommendations on maintenance. A working low-level alarm is useful in addition to giving another alert in case of low oil level.
Unusual Level Change Observation
Unusual level change in the transformer oil could be indicative of oil leakage, operating anomalies or other problems associated with the transformer. Any unusual level changes should not be ignored by maintenance staff based on reading alone.
Selection of Appropriate Magnetic Oil Gauge
It takes more than the cost of the gauge in selecting an appropriate magnetic oil gauge. Factors to be considered include the configuration of transformer and conservator, desired dial size, method of mounting, indication requirement, and alarm functionality.
Magnetic Oil Gauges (MOGs) that can be obtained from Dhruti Sales include: MOG SO-4, MOG SO-4 ATMS, MOG SO-6, MOG SO-6 ATMS, MOG SO-10 and MOG SO-10 ATMS.
It is necessary to choose the right model of the gauge based on the technical specifications of the transformer and not just use the same model for all transformers.
Conclusion for Magnetic oil gauge
The magnetic oil gauge is an important device to monitor the oil level in oil-filled transformers since it offers an easy-to-read oil level indication from the outside. The use of the floating and magnetic coupling design allows for the indication of any changes in the oil level in the transformer externally and offers a choice of additional alarms.
Correct installation and proper selection of the type and size of the gauge are vital to ensuring reliable operation. With several types and sizes of dials available, transformer owners and maintenance personnel may choose the gauge that is best for their transformer needs.
Dhruti Sales offers magnetic oil level gauges as well as other spare parts for transformers. Choosing the right magnetic oil gauge and performing regular transformer maintenance will help to ensure safe and efficient operation of the transformer.
