
FC 300 Operating Instructions
How to Install
Fuses
Branch circuit protection:
In order to protect the installation against electrical and fire hazard, all branch circuits in an
installation, switch gear, machines etc., must be shortcircuit and overcurrent protected according to the
national/international regulations.
Short circuit protection:
The frequency converter must be protected against short-circuit to avoid electrical or fire hazard. Danfoss
recommends using the fuses mentioned below to protect service personnel or other equipment in case of
an internal failure in the drive. The frequency converter provides full short circuit protection in case of a
short-circuit on the motor output.
Over current protection:
Provide overload protection to avoid fire hazard due to overheating of the cables in the installation. The
frequency converter is equipped with an internal over current protection that can be used for upstream
overload protection (UL-applications excluded). See par. 4-18. Moreover, fuses or circuit breakers can
be used to provide the over current protection in the installation. Over current protection must always
be carried out according to national regulations.
To comply with UL/cUL approvals, use pre-fuses according to the tables below.
200-240 V
VLT
Bussmann
Bussmann
Bussmann
SIBA
Littel fuse
Ferraz-
Shawmut
Ferraz-
Shawmut
Type RK1
Type J
Type T
Type RK1
Type RK1
Type CC
Type RK1
K2-K75
KTN-R10
JKS-10
JJN-10
5017906-010
KLN-R10
ATM-R10
A2K-10R
1K1-2K2
KTN-R20
JKS-20
JJN-20
5017906-020
KLN-R20
ATM-R20
A2K-20R
3K0-3K7
KTN-R30
JKS-30
JJN-30
5012406-032
KLN-R30
ATM-R30
A2K-30R
380-500 V, 525-600 V
VLT
Bussmann
Bussmann
Bussmann
SIBA
Littel fuse
Ferraz-
Shawmut
Ferraz-
Shawmut
Type RK1
Type J
Type T
Type RK1
Type RK1
Type CC
Type RK1
K37-1K5
KTS-R10
JKS-10
JJS-10
5017906-010
KLS-R10
ATM-R10
A6K-10R
2K2-4K0
KTS-R20
JKS-20
JJS-20
5017906-020
KLS-R20
ATM-R20
A6K-20R
5K5-7K5
KTS-R30
JKS-30
JJS-30
5012406-032
KLS-R30
ATM-R30
A6K-30R
KTS-fuses from Bussmann may substitute KTN for 240 V frequency converters.
FWH-fuses from Bussmann may substitute FWX for 240 V frequency converters.
KLSR fuses from LITTEL FUSE may substitute KLNR fuses for 240 V frequency converters.
L50S fuses from LITTEL FUSE may substitute L50S fuses for 240 V frequency converters.
A6KR fuses from FERRAZ SHAWMUT may substitute A2KR for 240 V frequency converters.
A50X fuses from FERRAZ SHAWMUT may substitute A25X for 240 V frequency converters.
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MG.33.A2.02 - VLT is a registered Danfoss trademark