Download PRD-ES-055 - Low Voltage Equipment

Integrated Management System
PRD-ES-055
LOW VOLTAGE EQUIPMENT
Name
Title
Prepared by
Vilas Tighare
Senior Automation
Engineer Projects
Reviewed by
Zaky Zeid
Electrical Manager
Projects
Approved by
Ahmed Al-Dhaheri
Vice President Projects
Sig.
EMIRATES STEEL
Low Voltage Equipment
PRD-ES-055
CONTENTS
1.
GENERAL
2.
CIRCUIT BREAKERS
3.
CONTACTORS
4.
THERMAL OVERLOAD RELAYS
5.
AUXILIARY RELAYS
6.
TIME RELAYS
7.
SPECIAL RELAYS
8.
PUSH BUTTONS AND INDICATOR LIGHTS
9.
MEASURING INDICATORS
10.
FIELD DEVICES
Issue No.: 01
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Issue Date: 08.06.2011
EMIRATES STEEL
Low Voltage Equipment
1.
PRD-ES-055
GENERAL
All low voltage (up to 1000V) equipment components shall be manufactured by a single
reputable electrical company having worldwide after sales services (e.g. ABB, AEG,
SIEMENS, GE, Schneider, Cutler Hammer).
2.
CIRCUIT BREAKERS
2.1
RATED CURRENT HIGHER THAN 630A
Circuit breakers for rated current higher than 630A shall be draw-out type air circuit
breakers (ACBs) equipped with motor operating mechanism with stored energy feature.
The ACBs shall comply as a minimum with IEC 60947; Low Voltage Switchgear and
Controlgear.
All circuit breakers shall have padlock facilities.
Adjustable electronic short circuit and temperature compensated thermal overcurrent
releases shall be fitted directly to the circuit breaker and automatically trip all 3 phases of
the circuit breaker simultaneously when the adjusted threshold setting value is reached.
The releases fitted shall be readily exchangeable.
Adjustment of the releases shall be from the front of the panels without the necessity of
withdrawing the circuit breaker portion from the fixed housing.
For indication purposes each circuit breaker shall be provided with minimum 1 NO and 1
NC auxiliary contacts.
2.2
RATED CURRENT MAX. 630A
Circuit breakers for rated current up to 630A shall be moulded case circuit breakers
(MCCBs). The circuit breakers shall preferably be plug-in on a fixed base, or at least
easily replaceable. In cases where they are used in motor starter units, the circuit
breakers are to be installed into the cassettes of the starter units.
The MCCBs shall comply as a minimum with IEC 60947; Low Voltage Switchgear and
Controlgear.
The MCCBs shall be rated to withstand and break the prospective full short circuit current
without the need for replacement.
2.3
MINIATURE CIRCUIT BREAKERS
Miniature circuit breakers (MCBs) shall be used in control and lighting circuits.
They shall have Type C, D or K characteristics and minimum breaking capacity of 10 kA in
compliance with IEC 60947-2 (IEC60947-4 for use with motor circuits).
Issue No.: 01
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Issue Date: 08.06.2011
EMIRATES STEEL
Low Voltage Equipment
3.
PRD-ES-055
CONTACTORS
Contactors for AC and DC operation shall be air break electromagnetic type and shall be
suitable for a minimum of 1 million operations and contactor size 00 for a minimum of 3
million operations. The contactors shall comply with IEC 60158-1.
The coils of the contactors shall be rated for 110V -50Hz maximum.
4.
THERMAL OVERLOAD RELAYS
Thermal overload relays for motor starters shall incorporate protection against single
phasing. They shall have adjustable settings and the range of adjustment shall be selected
such that the motor may operate continuously at 100% rated current and such that
inadvertent trips shall not occur during the motor start conditions.
Contactors with ratings of 630A or larger shall be fitted with electronic overload relays.
5.
AUXILIARY RELAYS
The coils of auxiliary relays in AC-circuits shall be rated for 110V, 50Hz max. and 24V DC
in case controlled directly by outputs of PLC subject to the switching limitations of the
output.
6.
TIME RELAYS
Only electronic time relays shall be used.
7.
SPECIAL RELAYS
The Contractor shall submit technical details of all special relays proposed for the
Purchaser’s approval. .
8.
PUSH BUTTONS AND INDICATOR LIGHTS
The mounting diameter of the devices shall be dia. 22mm and the rated operational
current Ie/AC-1 shall be minimum 10A. Indicator lamps shall be of LED type. The
equipment shall be suitable for operations in a typical steel works environment.
9.
MEASURING INDICATORS
All measuring indicators shall be installed in such a way that they can be read easily. The
size of measuring indicators shall be 96 x 96mm with measuring accuracy to Class 1.
Where LCD displays are used the character height shall be 8mm minimum.
10.
FIELD DEVICES
All field devices (limit switches, proximity switches, level switches, pressure switches,
temperature switches, tachometers, etc.) shall comply with applicable IEC or recognised
national standards standards.
Issue No.: 01
4 of 5
Issue Date: 08.06.2011
EMIRATES STEEL
Low Voltage Equipment
Issue
Status
01
Date
08/06/2011
Issue No.: 01
PRD-ES-055
Page / s
Revision Details
5
Formatted as per ISO corporate standard
5 of 5
Issue Date: 08.06.2011