SYSTEM DESIGN
16
EMX4i User Manual 710-14888-00C
3.10
Power Factor Correction
If power factor correction is used, a dedicated contactor should be used to switch in
the capacitors.
To use the EMX4i to control power factor correction, connect the PFC contactor to a
programmable relay set to Run. When the motor reaches full speed, the relay will
close and power factor correction will be switched in. Do not use the soft starter
relay output to directly switch in power factor correction.
K1
K1
1
2
4
3
20234.
A
1
Soft starter
2
Programmable output (set = Run)
3
Power factor correction contactor
4
Power factor correction
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.
3.11
Short Circuit Protection Devices (SCPD)
Fuses may be installed to protect the soft starter or the installation.
Type 1 Coordination
Type 1 coordination requires that, in the event of a short circuit on the output side of
a soft starter, the fault must be cleared without risk of injury to personnel. There is
no requirement that the soft starter must remain operational after the fault.
HRC fuses (such as Ferraz/Mersen AJT fuses) can be used for Type 1 coordination
according to IEC 60947-4-2 standard.
Type 2 Coordination
Type 2 coordination requires that in the event of a short circuit on the output side of
a soft starter, the fault must be cleared without risk of injury to personnel or
damage to the soft starter.
Semiconductor fuses for Type 2 circuit protection are additional to HRC fuses or
MCCBs that form part of the motor branch circuit protection.