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 overcurrent 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 drive. The frequency converter 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 frequency converter is equipped with an internal

overcurrent protection that can be used for upstream overload protection (UL-applications excluded). See par. 4-18

circuit breakers can be used to provide the overcurrent protection in the installation. Overcurrent protection must always be carried out according to

national regulations.

Fuses must be designed for protection in a circuit capable of supplying a maximum of 100,000 A

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 frequency converter.

FC Type

K25-K75

1K1-2K2

3K0-3K7

5K5-7K5

11K

15K-18K5