ABB UZE - 3. Drying

15
1ZSE 5492-115 en, Rev. 5
3. Drying
Drying of the on-load tap-changer is normally not required, see section 2.2, step 6.
The following temperatures and pressures between the on-load tap-changer tank and the
transformer tank are allowed when drying:
Pressure Standard on-load tap-changer On-load tap-changer with reinforced
barrier
Zero Up to 115 °C (239 °F) on the
transformer side.
Up to 90 °C (194 °F) inside the tank.
Up to 115 °C (239 °F) on the
transformer side.
Up to 90 °C (194 °F) inside the tank.
Up to 100 kPa Up to 60 °C (140 °F). Up to 90 °C (194 °F).
100–150 kPa Not allowed. Up to 60 °C (140 °F).
The temperature inside the motor drive cabinet must not exceed 70 °C (158 °F).
During or after drying the on-load tap-changer must not be operated until it has been lled
with oil. The motor-drive mechanism should not be included in a vacuum process, as the
process would remove the grease necessary for operation.
3 Drying