1.An oil thermometer which is common with oil-filled transformers can be considered as a partially effective device.
2.When equipped with alarm contacts connected to give remote warning of abnormally high oil temperature.
3. It’s location is such that, it naturally monitors the hottest fluid that exists in the transformer and is often used to start fan motors transformer equipped with automatic air blast to increase the name plate kVA rating
4. Thermometer cannot be relied upon as the fault-detecting device.
5. Transformer oil has much longer time constant than the winding themselves.
6. Alarm contacts used in conjunction with a oil thermometer are adjustable, but are typically set in such a way that brings on fan at liquid temperature of 60°C.
