10 Maintenance
10.1 Maintenance Schedule
In normal conditions, VACON
®
NX AC drives are maintenance-free. To make sure that the drive operates correctly and has a long life, we
recommend doing regular maintenance. Refer to the table for maintenance intervals.
Table 18: Maintenance Intervals and Tasks
Maintenance in‐
terval
Maintenance task
12 months
(1)
If the AC drive was in store for much longer than 12 months and the capacitors were not charged, speak to
the factory to get instructions before connecting the power.
6–24 months
(2)
•
Do a check of the tightening torques of the terminals.
•
Clean the heat sink.
•
Do a check of the mains terminal, motor terminal, and the control terminals.
•
Clean the cooling channel.
•
Make sure that the cooling fan operates correctly.
•
Make sure that there is no corrosion on the terminals, the busbars or other surfaces.
•
In FR10 Standalone (IP54), check and clean the door filters. Replace if needed.
5–7 years
Change the cooling fans:
•
the main fan
•
the internal IP54 (UL Type 12) fan
•
the cabinet cooling fan/filter
8–15 years
(3)
Replace the DC bus capacitors.
1
If the AC drive is kept in store
2
The interval is different in different environments.
3
The expected lifetime for the DC bus capacitor is between 8–15 years depending on the ambient temperature and the average load conditions. Expected service life is more than 15
years when the average load is 80% and the ambient temperature is 25 °C (77 °F).
10.2 Reforming the Capacitors
Context:
The electrolytic capacitors in the DC link rely on a chemical process to provide the insulator between the two metal plates. This process
can degrade over a period of years when the drive has been non-operational (stocked). The result is that the working voltage of the DC
link gradually falls.
The correct course of action is to ensure that the insulation layer of the capacitor is ‘reformed’ by the application of a limited current
using a DC supply. Current limiting ensures that the heat generated within the capacitor is kept at a sufficiently low level to prevent
any damage.
Maintenance
Operating Guide | VACON® NXS/NXP Air-cooled
AQ275638903263en-000301 / DPD00910
148 | Danfoss A/S © 2020.02
