MR VACUTAP VM-Ex, Installation And Commissioning Instructions

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5 Mounting
Maschinenfabrik Reinhausen GmbH 2020 100 5293079/01 EN VACUTAP
®
VM-Ex
5.4.3 Performing transformer ratio test before drying
NOTICE Damage to the on-load tap-changer!
Damage to the on-load tap-changer due to transformer ratio test being in-
correctly performed.
► Do not perform more than 250 tap-change operations on the on-load tap-
changer. If more than 250 tap-change operations are to be performed,
completely fill the oil compartment with insulating fluid and lubricate slid-
ing surfaces of contacts on the selector and selector gear with insulating
fluid.
► Only switch the on-load tap-changer from one operating position to the
next via the upper gear unit. You can use a short tube (diameter 25 mm)
with screwed-in coupling bolt (diameter 12 mm) with a hand wheel or
crank for this, for example. When using a drill, do not exceed a maximum
speed of 250 rpm.
► Always check the operating position reached through the inspection win-
dow in the on-load tap-changer head cover. Never overshoot the end po-
sitions, which are indicated in the connection diagram supplied with the
delivery.
► For multiple-column applications with a shared drive, link all on-load tap-
changer heads to one another using the horizontal drive shaft parts.
When actuating the change-over selector, a higher torque is required.
1. Switch the on-load tap-changer into the desired operating position. The di-
verter switch operation can be heard distinctly.
2. NOTICE! An incomplete tap-change operation may damage the on-load
tap-changer. After operating the diverter switch, continue to crank the
drive shaft of the upper gear unit for 2.5 revolutions in the same direction
in order to correctly complete the tap-change operation.
3. Perform the transformer ratio test.
4. Repeat the transformer ratio test in all operating positions.
5. Switch the on-load tap-changer into adjustment position (see the accom-
panying connection diagram for the on-load tap-changer).
After the transformer ratio test, open the kerosene drain plug in the oil com-
partment if the on-load tap-changer is to be dried with kerosene in the trans-
former tank. After drying, the diverter switch insert must be removed, the
kerosene drain plug in the oil compartment closed and the diverter switch
insert refitted.