MR VACUTAP VR, Installation And Commissioning Instructions

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6 Assembly: Bell-type tank design
Maschinenfabrik Reinhausen GmbH 2015 137 4349315/00 EN VACUTAP® VR®
Vacuum-drying in the transformer tank
Before you start vacuum-drying in the transformer tank, you must place a
connecting lead between the corresponding pipe connections and seal off
the pipe connections not being used with blank covers.
The on-load tap-changer head cover remains closed during the entire drying
process.
1. Establish a connecting lead either between the connections E2 and Q or
connections E2 and R on the on-load tap-changer head.
Figure 171: Connecting lead
2. Seal off unused pipe connections with a suitable blank cover.
Vacuum-drying in the transformer tank
1. Heat up the on-load tap-changer in air at atmospheric pressure with a
temperature increase of about 10 °C/h to a final temperature of maxi-
mum 110 °C.
2. Pre-dry the on-load tap-changer in circulating air at a max. temperature
of 110 °C for a period of 20 hours.
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.
Vapor-phase drying in the transformer tank
For vapor-phase drying in the transformer tank, you have to open the kero-
sene drain plug before drying so that the kerosene condensate can drain
from the oil compartment.
6.9.1
6.9.2