ABB SC Instruction Leaflet

ABB ABB ABB ABB
Effective: November 1998
Supersedes I.L. 41-766.1M, Dated August 1998
( | ) Denotes Changes since previous issue
!
CAUTION
Before putting protective relays into service,
remove all blocking which may have been
inserted for the purpose of securing the parts
during shipment. Make sure that all moving
parts operate freely. Inspect the contacts to
see that they are clean and close properly, and
operate the relay to check the settings and
electrical connections.
1.0 APPLICATION
The types SC and SC-1 current relays and the types
SV and SV-1 voltage relays are applicable where an
instantaneous plunger relay of high accuracy is
required. These relays are suitable for protective ser-
vice, and for auxiliary service where some of their
special features are desired. They are adjustable
over a wide range of voltage or current, are provided
with mechanical operation indicators, and have a cal-
ibrated scale which indicates the pickup setting. Both
contacts can readily be changed from "make" to
"break". The volt-ampere burden is low.
The SC and SV relays have a high ratio of dropout to
pickup (85 to 98% for the ac relays). The SC-1 and
SV-1 have a lower ratio of dropout to pickup (35 to
60% for the ac relays). The SV should not be used if
the normal applied voltage is in the vicinity of pickup
(plus or minus 10%).
All possible contingencies which may arise during installation, operation or maintenance, and all details and
variations of this equipment do not purport to be covered by these instructions. If further information is
desired by purchaser regarding this particular installation, operation or maintenance of this equipment, the
local ABB Power T&D Company Inc. representative should be contacted.
Printed in U.S.A.
ABB Automation Inc.
Substation Automation and Protection Division
Coral Springs, FL 33065
Type SC, SC-1
Instantaneous Current
and SV, SV-1Instantaneous
Voltage Relays
The SC may be used in fault detector applications
where direct energization of a breaker trip coil is
involved. It should not be used to energize a timer.
The SV should be used only in overvoltage applica-
tions.
2.0 CONSTRUCTION
The types SC, SC-1 and SV and SV-1 relays operate
on the solenoid principle. A U-shaped iron frame,
mounted on the molded base, supports the coil and
serves as the external magnetic path for the coil. The
coil surrounds a core and flux shunt. The upper end
of the core is threaded and projects through the
upper side of the frame, to which it is fastened by a
nut. A tube threaded on the outside at its lower end is
assembled in the core, and the threaded end extends
below the core. A Fluorosint
lower bearing for the plunger shaft, is assembled in
the lower end of this threaded tube. It is held in place
by two split spring sleeves, one above and one below
the bearing. The split sleeves must be compressed to
insert them in the tube and they will remain at any
position in which they are placed. The bearing for the
upper end of the plunger shaft is a Fluorosint
ing which is pressed in the upper end of the core.
This bearing is visible when the plunger is in the ener-
gized position. The plunger itself does not touch the
walls of the tube in which it moves.
A flux shunt which surrounds the core is screwed on
the tube, and its lower end projects below the relay
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Registered Trademark of The Polymer Corp.
Instruction Leaflet
41-766.1N
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bushing, which is the
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bush-