Danfoss VLT Series Design Manual page 91

®
VLT HVAC Drive Design Guide
5.2.7. Fuses
Branch circuit protection:
In order to protect the installation against electrical and fire hazard, all branch circuits in an in-
stallation, 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 in tables 4.3 and 4.4 to protect service personnel
or other equipment in case of an internal failure in the unit. 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.
Over current protection must always be carried out according to national regulations. The fre-
quency converter is equipped with an internal over current protection that can be used for
upstream overload protection (UL-applications excluded). See par. 4-18. Fuses must be designed
for protection in a circuit capable of supplying a maximum of 100,000 A
600 V maximum.
Non UL compliance
If UL/cUL is not to be complied with, Danfoss recommends using the fuses mentioned in table
4.2, which will ensure compliance with EN50178:
In case of malfunction, not following the recommendation may result in unnecessary damage to
the frequency converter.
VLT HVAC
200-240 V
K25-1K1
1K5
2K2
3K0
3K7
5K5
7K5
11K
15K
18K5
22K
30K
37K
45K
380-500 V
11K
15K
18K
22K
30K
37K
45K
55K
75K
90K
Table 5.2: Non UL fuses 200 V to 500 V
1) Max. fuses - see national/international regulations for selecting an applicable fuse size.
Max. fuse size
16A 1
16A 1
1
25A
1
25A
35A 1
1
50A
1
63A
63A 1
1
80A
1
125A
125A 1
160A 1
1
200A
250A 1
1
63A
1
63A
1
63A
63A 1
80A 1
100A 1
1
125A
1
160A
1
250A
1
250A
®
MG.11.B2.02 - VLT is a registered Danfoss trademark
5. How to Install
(symmetrical), 500 V/
rms
Voltage Type
200-240 V type gG
200-240 V type gG
200-240 V type gG
200-240 V type gG
200-240 V type gG
200-240 V type gG
200-240 V type gG
200-240 V type gG
200-240 V type gG
200-240 V type gG
200-240 V type gG
200-240 V type gG
200-240 V type aR
200-240 V type aR
380-480 V type gG
380-480 V type gG
380-480 V type gG
380-480 V type gG
380-480 V type gG
380-480 V type gG
380-480 V type gG
380-480 V type gG
380-480 V type aR
380-480 V type aR
5
91