Fuji Electric BW32AAG - Chapter 3; Selection Check Points; MCCB Selection Check Points

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3
Selection and application
3-1 Selection check points
3-1 Selection check points
When applying MCCBs to low-voltage circuits it is necessary
to consider their short-circuit breaking capacities, rated
voltages, rated currents, installation details, protection
systems, wire sizes and type of load (motor, capacitor,
mercury arc lamp, etc.)
Fig. 3-1 illustrates points to be considered when selecting
MCCBs. These are listed in Table 3-1.
3-1-1 MCCB selection check points
(1) Power supply system
s $ISTRIBUTIONSYSTEMTYPE.ETWORK
s 0OWERSUPPLYCAPACITY4RANSFORMERK6!
s 2EGULATION s!#OR$#
s &REQUENCY s,INEVOLTAGE2ATEDVOLTAGE
s #IRCUITS3INGLEPHASEPHASE
(2) Location
s %NVIRONMENTCONDITIONS
s !MBIENTTEMPERATURE
(3) Installation and connection
s -OTORCONTROLCENTERDISTRIBUTIONBOARD
s -AINORBRANCH
s &RONTMOUNTEDFRONTCONNECTION
s &RONTMOUNTEDREARCONNECTION
s &LUSHMOUNTED s0LUGIN
s $RAWOUT s!RCSPACECLEARANCE
s -OUNTINGANGLE s4ERMINATION
(4) Applications
s ,INEPROTECTION s-OTORPROTECTION
s )NSTANTANEOUSTRIP s-ARINEUSE
s 3PECIALPURPOSE7ELDERCAPACITORLIGHTS
(5) Short-circuit breaking capacity
s &ULLYRATED s3ELECTIVETRIP
s #ASCADEBACKUPTRIP
(6) Short-circuit current
s -##"SERIES s&RAMESIZE
(7) Loads
s -##"RATEDCURRENT s7IRESIZEBUSBARS
s #URRENTTIMECHARACTERISTICS
(8) Characteristics
s 7IREANDLOADEQUIPMENT
Mechanical and allowable thermal characteristics
s "REAKER
Breaking characteristics
Operation characteristics
(9) Operation
s 3WITCHINGFREQUENCYOPERATINGDURABILITY
s /PERATIONMETHOD
Remote – manual, motor driven
External operating handle (V and N)
(10) Accessories
s5NDERVOLTAGETRIP s!UXILIARYSWITCH
s3HUNTTRIP s!LARMSWITCH
s0ADLOCKING s4ERMINALCOVER
s-ECHANICALINTERLOCKDEVICE s%NCLOSURE
Fig. 3-1 Check points for selection
1. Power supply system
Transformer
2. Location
3. Installation and connection
5. Short-circuit breaking capacity
8. MCCB characteristics
9. Operation
10. Accessory
6. Short-circuit current
7. Loads and wires
8. Wire characteristics
8. Equipment characteristics
4. Application
7. Loads
Load