5.3 Fuse Tables
5.3.1 Protection
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 short-circuited and over-current protected according to 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 and equipment in case of an internal failure in the frequency
conveter. 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). 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.
5.3.2 Fuse Selection
Danfoss recommends using the following fuses which ensures compliance with EN 50178. In case of malfunction, not
following the recommendation may result in unnecessary damage to the frequency converter.
The fuses below are suitable for use on a circuit capable of delivering 100,000 Arms (symmetrical).
N165, N232, N262
380–500 V
type aR
N165, N232
575 V
type aR
Table 5.3 Recommended Fuses
VLT
Model
Bussman
PN
Littelfuse PN Littelfuse
PN
Bussmann
PN
Siba PN
Ferraz Shawmut
PN
Ferraz Shawmut PN
(Europe)
Ferraz Shawmut PN
(North America)
N165 T5 170M2621 LA50QS400-4 L50S-400
FWH-400A 20 610
31.400
A50QS400-4
6,9URD31D08A0400
A070URD31KI0400
N232 T5 170M4015 LA50QS500-4 L50S-500
FWH-500A 20 610
31.550
A50QS500-4
6,9URD31D08A0550
A070URD31KI0550
N262 T5 170M4016 LA50QS600-4 L50S-600
FWH-600A 20 610
31.630
A50QS600-4
6,9URD31D08A0630
A070URD31KI0630
Table 5.4 Fuse Options for 380–500 V Frequency Converters
VLT Model
Bussmann PN
Siba PN
Ferraz Shawmut European PN
Ferraz Shawmut North American PN
N165 T7
170M2619
20 610 31.315
6,9URD31D08A0315
A070URD31KI0315
N232 T7
170M4015
20 620 31.550
6,9URD32D08A0550
A070URD32KI0550
Table 5.5 Fuse Options for 575 V Frequency Converters
For UL compliance, use the Bussmann 170M series.
Specifications
Danfoss Turbocor
22
Danfoss A/S © 01/2015 All rights reserved.
MG35Q202
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