H المحركات وأجهزة التحكم

H. MOTORS & CONTROLS:

H.1. STANDARDS:

H.1.1 Motors and control shall comply with the following standards as appropriate:-

IEC/BS EN 60034
(All applicable parts)
Rotating electrical machines
BS 5000 Rotating electrical machines of particular types or for
particular applications
BS 5372 Specification for Dimensions of cable terminations for multi-
core extruded solid dielectric insulated distribution cables of
rated voltages 600/1000 V and 1900/3300 V having copper
or aluminium conductors
IEC/BS EN 60085

Electrical insulation - Thermal evaluation and designation
BS EN ISO 12100 Safety of machinery – General principles of design – Risk
assessment and risk reduction
IEC/BS EN 61800 Adjustable speed electrical power drive systems
IEC/BS EN 60068-2-6 Environmental testing - Part 2-6: Tests - Test Fc: Vibration
(sinusoidal)
IEC/BS EN 60068-2-27 Environmental testing - Part 2-27: Tests - Test Ea and
guidance: Shock
IEC/BS EN 61000-4-3 Electromagnetic compatibility (EMC) Testing and
measurement techniques. Radiated, radio-frequency,
electromagnetic field immunity test


H.1.2 This specification is not applicable to Direct Expansion Air Conditioning central units which are
covered under separate specification

H.1.3 The Contractor shall submit before ordering the following catalogues and technical details:

a) Technical catalogues for all types of motors with detailed list of the types, HP and speed.

b) Technical catalogues for all types of starters used with detailed list of types and rating of
contactors and the motor they control.

c) Technical catalogues for protection devices for motors above 50HP.

d) Wiring diagram for the starter/starters showing the protection devices, measuring
instruments.






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H.2 ELECTRIC MOTORS:

Motor shall generally be totally enclosed, fan cooled type protection class IP44 for indoor
motors and IP 55 for outdoor motors unless otherwise specified.

All motors shall comply fully with the requirements of the appropriate standard specification
mentioned above.

H.3 Motors shall be fully suitable for service in Kuwait climatic conditions.

H.4 Unless otherwise specified motors shall be of the squirrel cage type.

H.5 The rated voltage of the motors shall be:

a) 1-phase, 240V, 50 Hz for motors up to and including 1 H.P. Motors up to 5 H.P. may be
single phase under special conditions and prior approval shall be obtained.

b) 3-phase, 415 V, 50 Hz for motors ratings above 1 HP.
H.6 All motors windings and slot insulation shall be non -hygroscopic of class B, other superior
classes may be applicable so that the temperature rise of the motor as declared by the
manufacturer + ambient temp. is at least 10° C below the maximum operating temp. of the
insulating material used. The ambient temp. in plant room should be taken as 55ºC.

H.7 Motors shall be of high power factor.

H.8 Inherent protection shall be embedded in the motors 50 HP and above.

H.9 3-phase motors up to and including 7.5 H.P may be started direct on line (D.O.L). Motors above
7.5 H.P. and up to 50 HP shall be of the reduced current or reduced voltage starting , such as
Star-Delta Starter, to ensure that starting current does not exceed 2.5 times the full load current .
Motor above 50 HP shall have solid state soft motor starting system (Soft starter).

The soft starter shall be a power electronic type motor starting device. It shall control the voltage
applied to the motor smoothly by varying the conduction angle of the solid stage a.c. switches
which can be triacs, reverse parallel connected SCR -diode circuit or reverse parallel connected
SCR-SCR circuit, etc. or using other similar technique. It shall be manufactured in conformance
with IEC/BS EN 60068-2-6, IEC/BS EN 60068-2-22 and IEC/BS EN 61000-4-3.

UNDER NO CIRCUMSTANCES shall the power factor correction equipment be connected
between the soft starter and the motor. If power factor correction equipment is employed, it shall
be connected to the supply side of the soft starter.

H.10 Motor starters shall be mounted on mounting plates enclosed in a separate cell.

Individual motor starter shall be enclosed in a casing protection IP 41 for indoor mounting and
IP 55 for outdoor mounting and shall house all the starter components, contactors, protection
devices, metering...etc. as applicable.

H.11 Each motor rated of 1HP and above shall be provided with:

a) Means of isolation from electricity supply for purpose of adjustment and maintenance.




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b) M.C.C.B's or fuses suitable rating for short circuit protection.

c) Means for automatically disconnecting it from the electricity supply in the event of:

i) Failure of supply
ii) Serious drop in voltage
iii) Flow of excess current

Where main incomer for a motor control center (MCC) is provided with audible and visual alarm
earth leakage relay (Clause B.13) motors 45 HP and above shall be provided with individual earth
leakage relay (Clause B.12).

For individual motor starters contr olling motors less than 50 HP and above 15 HP shall be
provided with R.C.C.B. (Clause. C.4). Motors from 50 HP and above shall be provided with earth
leakages relay (Clause B.12) unless the M.C.C.B. feeding the motor starter is provided with earth
leakage protection.

H.12 The over load relays provided with motor starters shall be of the magnetic type or of the thermal
type with automatic compensation for variation in ambient temp. between 0°C and 55°C. The
over load shall be of 3 phases.

H.13 For motors 25 HP and above current transformer operated over load protection shall be used.
Separate single phase preventer shall be provided for motors 25 HP and above.

H.14 Unless otherwise specified, starters for motor rated 25 HP and above s hall be provided with an
ammeter with selector switch.

H.15 Unless otherwise specified starters for motors rated 25 HP and above shall be provided with red
and green indicating lamps to show status of each motor.

H.16 Motor starters and push buttons shall be clearly labeled showing the machines they control.

H.17 Stop push buttons shall have large mushroom head and/or coloured red.

Start push buttons shall be shrouded to prevent accidental operation and must be coloured green

H.18 Motors driving A ir handling units shall be controlled by Latch type contactors unless the Air
handling unit is remote controlled from the Motor Control Centre.

H.19 Starter controlling chiller compressors shall conform to NEMA/ANSI and NEC standards
normally used with the chillers provided.

a) The chiller manufacturer confirms that they normally use the offered starter with their
chillers and recommend its use.

b) Fulfill the requirements of starter specified above.

H.20 Each starter in addition to the auxiliary contacts used for electrical interlocking shall have at
least one extra normally opened and one normally closed contact.






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