Danfoss VLT Micro Drive FC 51 Operating Manual page 7

VLT® Micro Drive FC 51
Operating Guide
The [Off/Reset] key is not a safety switch. It does not disconnect the drive from mains.
DISCHARGE TIME
The drive contains DC-link capacitors, which can remain charged even when the drive is not powered. High voltage can be
present even when the warning indicator lights are off.
Failure to wait the specified time after power has been removed before performing service or repair work could result in death or
serious injury.
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Stop the motor.
-
Disconnect AC mains, permanent magnet type motors, and remote DC-link supplies, including battery back-ups, UPS, and
DC-link connections to other drives.
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Wait for the capacitors to discharge fully. The minimum waiting time is specified in the table Discharge time and is also visible
on the nameplate on top of the drive.
-
Before performing any service or repair work, use an appropriate voltage measuring device to make sure that the capacitors
are fully discharged.
Table 1: Discharge Time
Size
M1, M2, and M3
M4 and M5
Leakage current (>3.5 mA)
Follow national and local codes regarding protective earthing of equipment with a leakage current >3.5 mA. AC drive technology
implies high frequency switching at high power. This generates a leakage current in the ground connection. A fault current in the
drive at the output power terminals might contain a DC component, which can charge the filter capacitors and cause a transient
ground current. The ground leakage current depends on various system configurations including RFI filtering, shielded motor ca-
bles, and drive power.
EN/IEC61800-5-1 (Power Drive System Product Standard) requires special care if the leakage current exceeds 3.5 mA. Reinforce
Grounding in 1 of the following ways:
• Grounding wire of at least 10 mm
• 2 separate ground wires both complying with the dimensioning rules.
See EN 60364-5-54 § 543.7 for further information.
Using RCDs
Where residual current devices (RCDs), also known as earth leakage circuit breakers (ELCBs), are used, comply with the following:
• Use RCDs of type B that can detect AC and DC currents.
• Use RCDs with an inrush delay to prevent faults due to transient ground currents.
• Dimension RCDs according to the system configuration and environmental considerations.
Motor thermal protection
Motor overload protection is possible by setting parameter 1-90 Motor Thermal Protection to [4] ETR trip. For the North American
market: Implemented ETR function provides class 20 motor overload protection, in accordance with NEC.
Installation at high altitudes
For altitudes above 2000 m (6562 ft), contact Danfoss regarding PELV.
Danfoss A/S © 2020.09
N O T I C E
W A R N I N G
Minimum waiting time (minutes)
4
15
2
(8 AWG).
AQ348848915086en-000101 / 130R0943 | 7
Safety