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8.3 Fuses
Branch circuit protection:
In order to protect the installation against electrical and fire hazards, all branch circuits in an installation, switch gear, machines, etc. must be short-
circuited and overcurrent protected according to national/international regulations.
Short-circuit protection:
The adjustable frequency drive must be protected against short-circuit to avoid electrical or fire hazard. Danfoss recommends using the fuses mentioned
below to protect service personnel and equipment in case of an internal failure in the drive. The adjustable frequency drive provides full short-circuit
protection in case of a short-circuit on the motor output.
Overcurrent protection:
Provide overload protection to avoid fire hazard due to overheating of the cables in the installation. The adjustable frequency drive is equipped with an
internal overcurrent protection that can be used for upstream overload protection (UL applications excluded). See par. 4-18
Current Limit
. Moreover,
fuses or circuit breakers can be used to provide the overcurrent protection in the installation. Overcurrent protection must always be carried out according
to national regulations.
Non-UL compliance
If UL/cUL is not to be complied with, we recommend using the following fuses, which will ensure compliance with EN50178:
In case of malfunction, not following the recommendation may result in unnecessary damage to the adjustable frequency drive.
Max. fuse size
1)
Min. rated voltage
Type
K25-K75
10A
200–240 V
type gG
1K1-2K2
20A
200–240 V
type gG
3K0-3K7
32A
200–240 V
type gG
5K5-7K5
63A
200–240 V
type gG
11K
80A
200–240 V
type gG
15K-18K5
125A
200–240 V
type gG
22K
160A
200–240 V
type aR
30K
200A
200–240 V
type aR
37K
250A
200–240 V
type aR
Max. fuse size
1)
Min. rated voltage
Type
K37-1K5
10A
380–500 V
type gG
2K2-4K0
20A
380–500 V
type gG
5K5-7K5
32A
380–500 V
type gG
11K-18K
63A
380–500 V
type gG
22K
80A
380–500 V
type gG
30K
100A
380–500 V
type gG
37K
125A
380–500 V
type gG
45K
160A
380–500 V
type gG*
55K-75K
250A
380–500 V
type gG*
* Type gG is not applicable to frame sizes C2 in IP21 enclosure and frame size C4. In this case, type aR is recommended.
Max. fuse size
1)
Voltage
Type
11-22K (B2)
63 A
525–690 V
type gG
30K (C2)
80 A
525–690 V
type gG
37K (C2)
100 A
525–690 V
type gG
45K (C2)
125 A
525–690 V
type gG
55K-75K (C2)
160 A
525–690 V
type gG
P90 - P200
380–500 V
type gG
P250 - P400
380–500 V
type gR
1) Max. fuses - refer to national/international regulations to select an appropriate fuse size.
8 Electrical Installation
FC 300 Design Guide
8-22
MG.33.BC.22 - VLT
®
is a registered Danfoss trademark
8