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GEK-1256
FAUL T DETECTOR RELAYS
TYPE CHC13D(-)A
INTRODUCTION
This
instruction
book,
together with
insert
booklet GEK-1253,
forms
the
instructions for the Type CHC13D(-)A relays.
The CHC13D(-)A relay includes a three phase, high-speed induction cup unit (PFD),
a target (T) and a telephone-type auxiliary unit (A), mounted in an 5-2 drawout case.
It is similar to the CHC11A, described in instruction book GEK-1253, except that it
does not have a ground fault detector.
APPLICATION
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The CHC13D relay is designed as a current fault detector, for use in conjunction
with distance relays, to prevent tripping the circuit breaker or operation of the
associated timer during loss of relay potential supply for reasons other than a system
fault.
This can occur as a result of:
(1) short circuits or open circuits involving
the potential supply; (2) switching (with certain configurations of power circuits); or
(3) use of line-side potential supply for the relays.
In the latter instance, the
fault detector protects the associated timer against possible burnout when the breaker
is open, and avoids false breaker retripping at the instant of reclosure.
DESCRIPTION
The main operating unit of this relay is similar the the CHC11A in construction,
except for the moving element stop screw, which is located in the rear on the left-hand
side of the relay.
Its operating characteristics are the same as the PFD unit
described in instruction book GEK-1253.
The holding coil assembly prevents the fault detector contact from arcing when
operating near its minimum pickup value.
The holding action, while sufficient to
prevent arcing, does not impair the dropout value to an objectionable degree.
Dropout
will be in the order of 80 percent of pickup when the unit is set at the minimum value
of its adjustable range, and increases when the pickup setting is raised.
The holding coil force is controlled by the air gap between the holding coil pole
pieces and the armature on the moving contact, and it should not require any adjustment
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from the normal factory setting.
The air gap between the holding coil pole pieces and
the armature should not be less than 0.015 inch.
(Cover Photo 80339179)
These Instructions do not purport to cover all details or variations in equipment nor to provide for
every possible contingency to be met
In
connection with installation,
operation or maintenance.
Should
further information 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 Company.
To the extent requIred the products described herein meet applicable ANSI,
IEEE and NEMA standards;
but no such assurance
15
given with respect
to
local codes and ordinances because they vary greatly.
*Indicates Revision
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