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4.8 Power Factor Correction
If power factor correction is used, a dedicated contactor
should be used to switch in the capacitors. Power factor
correction capacitors must be connected to the input side
of the soft starter.
CAUTION
Power factor correction capacitors must be connected to
the input side of the soft starter. Connecting power factor
correction capacitors to the output side will damage the
soft starter.
4.9 Fuses
4.9.1 Power Supply Fuses
Semiconductor fuses can be used for Type 2 coordination
(according to IEC 60947-4-2 standard) and to reduce the
risk of damage to SCRs from transient overload currents.
HRC fuses (such as Ferraz AJT fuses) can be used for Type
1 coordination according to IEC 60947-4-2 standard.
NOTE
Adaptive Acceleration Control (AAC) controls the motor's
speed profile, within the programmed time limit. This may
result in a higher level of current than traditional control
methods.
For applications using Adaptive Acceleration Control to
soft stop the motor with stop times greater than 30
seconds, motor branch protection should be selected as
follows:
•
Standard HRC line fuses: Minimum 150% motor
full load current
•
Motor rated line fuses: Minimum rating 100/150%
motor full load current
•
Motor control circuit breaker minimum long time
setting: 150% motor full load current
•
Motor control circuit breaker minimum short time
setting: 400% motor full load current for 30
seconds
Fuses recommendations are calculated for 40
°
C, up to
1000 m.
NOTE
Fuse selection is based on a 400% FLC start for 20 seconds
in conjunction with standard published starts per hour,
duty cycle, 40
°
C ambient temperature and up to 1000 m
altitude. For installations operating outside these
conditions, consult your local supplier.
NOTE
These fuse tables contain recommendations only, always
consult your local supplier to confirm the selection for
your particular application.
For models marked - there is no suitable fuse.
Electrical Installation
MCD 500 Operating Instruction
22
MG17K402 - VLT
®
is a registered Danfoss trademark
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