General
The type CVR-1 Voltage Regulating Relay
is in reality a "control package" designed to
control load tap changers. The major com
ponents of the CVR-1 relay are an induction
disk type voltage sensitive relay, two
atL'\:
iliary or pilot relays, two motor control re
lays, line drop compensator, and a reactor.
All components are in a drawout chassis
(Figures 1 and
6)
so that the complete relay
may be interchanged from unit to unit or
removed for testing and inspection.
The
Flexitest® switch base is made an integral
part of the CVR-1 relay to facilitate con
necting and testing the relay. The case in
which the relay is mounted for tap changer
control is equipped with the mating portion
of the Flexitest® switch.
Installation
The CVR-1 relay is usually mounted in the
tap changer control panel. Before putting the
relay in service, remove any blocking in
serted for the purpose of securing parts
during shipment; make sure that all parts
operate freely, and inspect the contacts to
see that they are clean and close properly.
Check the gaps of the permanent magnet and
of the electromagnet and clean them if any
foreign material is present.
Operate the
relay to check the settings and electrical
connections.
Operation
The sensing element of the CVR-1 relay is
an induction disk voltage relay with a set of
single pole double throw contacts. Sealing
circuits for the auxiliary relay are incor
porated into the circuit to insure long contact
life and positive operation.
Figure 2 shows schematically the rela
tion between the principle components of the
CVR-1 relay voltage sensing circuit, while
Figures 3 and
4
show the internal schematic
and internal wiring of the actual CVR-1
relay.
Page 3
Fig. 1- CVR-1 Relay Removed
from
Case
A reactor connected in series with the
voltage sensing element is a large portion of
the impedance of this circuit. This feature
minimizes the effect of resistance varia
tions due to temperature changes. The re
actor is also used in the line drop com
pensator circuit.
The voltage coil on the lower pole of the
voltage sensing element supplies a current
to the coil on the upper pole by transformer
action.
The alternating fluxes induced in
these poles are in quadrature. The alter
nating flux cutting the induction disk induces
eddy currents in the disk of the relay which
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