COMEM RDR-MK II Manual De Instrucciones página 7

Attention:
the transformer cannot operates with closed shutter valve as this
could cause an explosion with great damages to people and plant.
We strongly recommend to the user to reset the shutter valve always
after its operating and before to set the transformer at work.
Working and adjustment
The shutter valve main function is to block automatically the oil flow through a disk
valve.
This valve closes itself against a gasket when the force of friction of the disk, against the
oil flow, is superior to the thrust towards high caused by a float.
The operating threshold of the shutter valve can be adjusted through a flow governor
(see picture 2 , pos. 5 ); it allows to vary the disk valve opening according to the maxi-
mum flow rate needed for the transformer.
It is recommended to adjust the disk valve - through flow measurers - by screwing or
unscrewing the governor ( 5 ) till the fit flow value has been got.
The reference notches, numbered from 1 to 4 and placed on the governor ( 5 ), can help
to carry out the adjustment. They have only a reference value as the adjustment has to
be carried out through proper instruments.
Position 1 refers to the maximum opening of the disk valve, position 4 to minimum one.
The secondary function of Comem shutter valve is to signal the happened operating
through electric contacts. These contacts are magnetic type, they are placed inside the
shutter valve, and they are connected to the terminal box (see picture 2 , pos. 4 ). Only
the wiring diagram shown in picture 1 is available, with two separate and changeover
contacts.
Wiring diagram showed in picture 1 states the contacts position with the disk valve
closed.
Installation and recommendation
The shutter valve has to be installed between the conservator and the Buchholz relay. It
is also possible to connect the shutter valve in series, that is to say just before Buchholz
relay.
The red arrow placed on the upper part of the shutter valve states the direction towards
the conservator.
The shutter valve is supplied with a reset lever already installed on its right side; it is
possible to move the reset lever on the left side by using the spring supplied with the
shutter valve.
After having filled the transformer with oil, it is necessary to breathe out the air taken by
the shutter valve by opening the breather cocks (see picture 2 , pos. 1 ).
COMEM
COMEM S.p.A.
GB
7