5 Crucial Maintenance Tips for Electrical Transformers

Transformer maintenance ensures that its external and internal parts and other accessories are always in good condition, fit for use, and run safely at all times. It also helps maintain the transformer’s historical data. Maintenance helps keep your transformer healthy while ensuring it doesn’t malfunction. Electrical transformer maintenance can be corrective, predictive, or preventive. It can be done as condition-based maintenance or periodically.

If maintenance is recommended, it’s done based on oil sample analysis, inspections, equipment tests, electrical measurements, monitoring, or temperature measurements using heat-sensitive cameras. This article outlines five crucial maintenance tips for electrical transformers.

1.  Conduct transformer oil testing

Transformer oil is crucial in your equipment’s cooling process and needs periodic testing because it slowly deteriorates and ensures proper function over time. When analyzing the oil, you should take a sample from your transformer and get it properly tested to look for possible contaminants. The test can be done in a lab or on-site where portable test tools are used. When oil testing standard or custom transformers, measure the transformer oil’s dielectric strength or Breakdown Voltage to ensure the transformer stays completely operational.

A high dielectric strength implies the device will have better electrical resistance to ensure it doesn’t malfunction easily. Oil testing includes surface tension which helps determine the acid level present in the oil to prevent or discover sludge formation early. You should also use oil color as it shows the presence of contaminants and the age and quality of your oil. Check your water or moisture content because it affects dielectric strength, reducing the transformer’s effectiveness.

2.   Avoid overloading the transformer

Overload happens when transformers are forced to carry current over the rated capacity, which is determined by manufacturers. The rated capacity represents the optimum current a transformer can safely carry without causing damage or overheating. Overloading your transformer affects its efficiency and performance and may even result in failure or damage. The overload amount a transformer can safely handle depends on multiple factors, including rated capacity, cooling system, and transformer design. While transformers are meant to carry some level of overload for specific periods, sustained overloads can cause failure or damage.

Increased load demand, voltage fluctuations, or a fault in your electrical system may cause transformer overloading. For effective transformer maintenance, ensure its current capacity doesn’t exceed the level specified by the manufacturer. Maintain a stable voltage degree to avoid overloads resulting from voltage fluctuations. You should also install protection devices like fuses and circuit breakers to prevent overloading caused by earth faults or short circuits.

3.  Schedule transformer inspections

Electrical devices deteriorate with use and age. They’re also subject to contaminants and possible faults. Annual transformer inspections are a simple way to diagnose faults, like loose connections on LV (low voltage) equipment or oil aging on high voltage (HV) equipment and air bubbles. These faults usually increase failure risk and minimize the equipment’s lifespan, lowering your transformer’s efficiency. To keep your transformer running optimally, conduct annual inspections of any issues resulting in the device failing or becoming unsafe.

These checks help ensure you’re running within your insurance’s guidelines, plus the constantly changing health, fire, and safety regulations. Annual transformer evaluations spot changes and ascertain your electrical equipment’s optimal functioning while guaranteeing high-efficiency methods.

4. Maintain the silica gel and breather

Silica gel breathers are used in transformers to let air flow out of and into the transformer tank and prevent dust and moisture ingress. The liquid has a blue tint when the silica gel breather is initially installed. However, after an operation period, the tinted crystals’ color slowly changes to pink, a sign that your silica gel is getting saturated and losing absorbent features. When pink crystals are prevalent, you should change or reactivate the silica gel.

You can reactivate the silica gel by heating it in a thin pan for about two to three hours at 150 to 200 degrees for the crystals to regain the original tint (blue). Before filling the breather with silica gel, ensure all its parts are clean and dry. Ascertain that the oil level in the oil cup is right and the breather isn’t choked but is free for air passage.

5. Hire a professional transformer maintenance technician

You shouldn’t DIY transformer maintenance, particularly if you lack the necessary skills and experience. How you handle a transformer can impact its performance, lifespan, and efficiency. Professional transformer maintenance technicians have the education, skills, and expertise to ascertain equipment transformer care. Additionally, they have the right tools and procedures to ensure smooth operation, reduced failure, and a longer lifespan.


Regular transformer maintenance promotes optimal performance and efficiency. Consider implementing these electrical transformer maintenance tips to preserve your equipment.


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