What Causes a Dry Type Transformer to Overheat?
While many dry type transformer designs can last several decades, constant exposure to heat above a unit's limit will significantly decrease its service life. Low-quality transformers with substandard insulation and windings often generate more heat, leading to an increased temperature rise, also called C-rise.
The average temperature increase of a unit over the ambient temperature when the transformer is fully loaded determines the C-rise. The better a transformer's performance and efficiency, the lower the C-rise.
Several factors that can cause a transformer to overheat or increase its C-rise include:
1.Improper load rating selection: Selecting a transformer with a rating that can handle the intended application is crucial. The load rating is the maximum power a unit can efficiently and safely handle without causing damage or overheating.
2.Inadequate airflow: Installing a dry type unit in a location with sufficient airflow and ventilation is vital. Even if a transformer is in an enclosure with air vents, it should not be near anything obstructing the airflow.
3.Poor Insulation: Various insulation types transfer or dissipate heat at different rates. ELSCO uses DuPont Nomex Type 410 insulation because it offers effective protection against temperature failure.®
4.Low-quality windings: Prolonged temperatures exceeding the design temperature can break down the windings' dielectric strength, leading to power surges, hot spots or total system failure. Different winding methods can also help improve a transformer's C-rise.
