5 Mounting
Maschinenfabrik Reinhausen GmbH 2020
93
7545652/00 EN
VACUTAP
®
VR-Ex
Figure 91: Kerosene drain plug
5.3.5.2.4 Drying the on-load tap-changer
NOTICE
Damage to the on-load tap-changer head cover and on-load tap-
changer accessories.
Both the on-load tap-changer head cover and the on-load tap-changer ac-
cessories will become damaged if they are dried.
► Never dry the on-load tap-changer head cover or the following acces-
sories: motor-drive unit, drive shaft, protective relay, pressure monitoring
device, pressure relief device, bevel gear, temperature sensor, oil filter
unit.
1. Supply kerosene vapor at a temperature of around 90°C. Keep this tem-
perature constant for 3 to 4 hours.
2. Increase the kerosene vapor temperature by approx. 10°C/hour to the de-
sired final temperature of max. 125°C at the on-load tap-changer.
3. Vacuum-dry on-load tap-changer at between 105°C and maximum 125°C
for at least 50 hours.
4. Residual pressure of no more than 10
-3
bar.
5.3.5.2.5 Closing kerosene drain plug
►
NOTICE!
An open kerosene drain plug leads to insulating fluid escaping
from the oil compartment and therefore to damage to the on-load tap-
changer. Close kerosene drain plug (tightening torque 20 Nm).