What is a Transformer Breather?
A transformer breather (silica gel breather) is a simple device that keeps moisture out of the transformer. We fit it to the pipe coming out from the transformer conservator tank. When the transformer heats up, the oil expands. When it cools down, the oil contracts. This creates a breathing action. Air goes in and out of the transformer.
The silica gel breather removes moisture from the air before it enters the transformer. Dry air is very important. Moisture can damage the insulation inside the transformer. It can reduce the life of the transformer. The breather protects the transformer oil from moisture. The device gets its name because it uses silica gel crystals as the main drying agent. These crystals absorb water vapor from the air very effectively. Thus, the transformer oil remains clean and dry.
Construction Details of Silica Gel Breather
The transformer breather (silica gel breather) has a simple construction. It contains a cylindrical container made of transparent plastic. This container holds blue or orange silica gel crystals. Additionally, the breather has an oil pot at the bottom. Metal fittings connect the breather to the pipe coming out from the transformer conservator tank.
The silica gel crystals change color when they absorb moisture. Blue silica gel turns pink after saturation. Similarly, orange silica gel turns green. Obviously, this color change helps in easy monitoring.
Purpose of the Oil Pot in the Breather
There is an oil pot that sits at the bottom of the transformer breather. It contains transformer oil and serves as a secondary filter. When air enters the breather, it first passes through this oil. The oil traps dust particles and large impurities. After that, the air moves in through the silica gel.
Moreover, the oil pot acts as a seal. It prevents moisture from entering during rainy seasons. Obviously, the oil creates a barrier between the outside air and the silica gel.
Preventive Maintenance and Regular Checking of Breather
You must check the transformer breather every month. Look at the silica gel color. Replace it when it turns pink. Although you can reuse dry silica gel. Heat it in an oven at 150 degrees Celsius for three hours. Then, it will turn blue again.
Check the oil level in the oil pot. Add fresh transformer oil if needed. Clean the oil pot every six months. Remove dirt and sludge from the bottom. Check all connections for leaks. A leaking breather cannot protect your transformer properly.
Smart Transformer Breather
Yes, smart breathers exist now. These modern devices have sensors inside them. The sensors monitor the silica gel condition automatically. They send alerts when the silica gel needs replacement. Some smart breathers connect to your phone or computer.
These breathers reduce maintenance work. You do not need to check them manually every month. They tell you exactly when service is needed. Smart breathers are costlier than normal breathers. Large power transformers use them more often.
Recommended Sizes of Breathers
Small transformers up to 5 MVA use breathers with 1 kg silica gel capacity. Whereas medium transformers from 5 MVA to 20 MVA need 2 kg capacity breathers. Large transformers above 20 MVA require 3 kg or bigger breathers.
The breather size depends on the transformer tank size. Obviously, bigger tanks need bigger breathers. The manufacturer recommends the correct size. Always follow their guidelines.
Essential Information on Silica Gel Transformer Breather
Never run a transformer without a working breather. Even a few days without proper breathing can cause damage. Keep spare silica gel ready always. Store it in airtight containers.
Use only high-grade silica gel. Obviously, poor-quality gel does not absorb moisture well. The gel should meet industrial standards. Check the breather after heavy rains. Humidity is very high during monsoons.
IS and IEC Standards for Silica Gel Breather
The Indian Standard IS 2026 covers specifications for transformer breathers. Additionally, the IEC standard IEC 60076 discusses transformer accessories, including breathers. These standards ensure quality and safety. Always buy breathers that meet these standards.