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GEK—65583
TYPE
IJCS1E
CURRENT
BALANCE
RELAY
DESCRIPTION
The Type IJC5IE current balance relay consists of three mechanically-separate
but
electrically
interconnected
induction—disk
units
mounted
in
a
large
size,
single-end drawout case.
The outline and panel drilling dimensions for the Type
IFC51E
are shown
in Figure 13.
Each unit consists of a disk and shaft assembly
which carries the moving contact.
Each disk is actuated by two U-magnet and coil
assemblies, the operating coil on the left—hand side and the restraint coil on the
right—hand side (front view).
Each disk
shaft is restrained by a spiral
spring
which holds the contact open when the relay is de-energized.
There is a target seal—in unit mounted on the front and to the left of the
shaft
of each
induction—disk
unit.
This
unit
has
its coil
in
series and
its
contacts in parallel with the contacts of the main unit.
APPLICATION
The Type IJC51E relay is recommended for the protection of three—phase lines
and machines against damage
from phase unbalance or single—phase operation.
The
relay is typically applied where currents in the three phases are normally balanced.
The external connection in Figure 14 illustrates a typical application.
The relay
compares the currents in each phase with those in each of the other phases
Any
increase
in current
in
the protected circuit,
regardless of magnitude, will
not
cause a relay operation as long as the unbalance does not exceed the slope setting
of the relay, 115, 125, 135 or 150%.
When a fault or unbalance occurs in the machine or line, and causes the current
in one of the phases to exceed that in the others by more than the slope setting,
the torque produced by the operating coil will be greater than that of the restraint
coil, and the relay will operate to trip the breaker.
The
IJC51E
relay
can
be
classified
as
a
relay
which
protects
against
discontinuity of balanced-phase conditions, rather than as a fault—protective relay.
When used for protection against single-phase operation of a machine, it must have a
time setting of such length that it will not trip the machine on an external single-
phase
fault.
Such
a
time delay must
permit
selective
tripping
by
the relays
protecting the faulted circuit.
These .1nstructons do
or
purport to cover
412 deta1ls or vartions in equipnt nor to provide for
evert possible contingency to
be met in
connection ..'ith installation,
operation
or maintenance.
Should
further informaton be desired or should particuLar problems arise which are not covered sufficiently for
the purchaser's purposes,
the matter should be referred to the General Electric Cosçany.
To the extent required the products described herein meet applicable ANSI.
IFEE and NFF(4 standards;
bit
flO
Such assurance is
qiwer, .'ith respect to
local codes and ordinances because they vary greatl!.
3
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