Hermetic protection relay

It is preferred in hermetic designs. The relay shows the gas discharge, oil temperature and internal pressure in the boiler. It is used in transformers greater than 500 KVA. The relay has two contacts for each of them for gas discharge, boiler pressure and oil temperature.

Magnetic oil level indicator

It is used to monitor the oil level in the oil expansion tank. The change of transformer oil is shown on the oil level indicator with a float connected magnetically. The magnetic oil level indicator depends on the diameter of the same expansion tank. If desired, level indicators with contact are also used.

Alcohol thermometer

Alcohol thermometer is only used to monitor the temperature of transformer oil and it is non-contact.


As a connection to the oil expansion tank, when the oil volume changes, it captures the moisture in the air passing through it and prevents moisture from passing into the oil. The size of the dehumidifier is used depending on the amount of oil and air.

Pressure relief valve

It is preferred in hermetic designs. It protects the Transformer tank in case of sudden pressure increase. It is mounted on the cover. If the boiler is exposed to the internal pressure set by the valve, the valve opens and it prevents the boiler from rupturing by compensating the pressure thanks to the oil discharge. Then it turns off again automatically. It can be used with contact when desired.

Buchholz role

It is connected with pipes between the transformer tank and the oil expansion tank. It is used to protect the transformer in case of a malfunction in the electrical equipment inside the transformer, in a malfunction that may occur in the electrical equipment inside the transformer. happens. The relay has two independent contacts for Open and Alarm. These; It is 5 A, 250 VAC or 0.2 A, 250 VDC.
Contact oil temperature thermometer
There is a Maximum indicator showing the Maximum temperature reached by the oil in the transformer and it can be reset with a button at the bottom. Oil temperature can be read up to 120 oC. There are two adjustable contacts. The electrical value of micro switches is 5 A 250 VAC or 0.2 A, 250 VDC.