Leakage Current (>3.5 Ma); Grounding Using Shielded Cable; Access - Danfoss VLT FC 103 Operating Instructions Manual

Installation
• •
Do not ground one frequency converter to
another in a "daisy chain" fashion
•
Keep the ground wire connections as short as
possible
•
Using high-strand wire to reduce electrical noise
is recommended
•
Follow motor manufacturer wiring requirements
2.4.2.1 Leakage Current (>3.5 mA)
Follow national and local codes regarding protective
earthing of equipment with a leakage current > 3.5 mA.
Frequency converter technology implies high frequency
switching at high power. This will generate a leakage
current in the earth connection. A fault current in the
frequency converter at the output power terminals might
contain a DC component which can charge the filter
capacitors and cause a transient earth current. The earth
leakage current depends on various system configurations
including RFI filtering, screened motor cables, and
frequency converter power.
EN/IEC61800-5-1 (Power Drive System Product Standard)
requires special care if the leakage current exceeds 3.5 mA.
Earth grounding must be reinforced in one of the
following ways:
•
Earth ground wire of at least 10 mm
•
Two separate earth 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 only which are capable of
detecting AC and DC currents
Use RCDs with an inrush delay to prevent faults
due to transient earth currents
Dimension RCDs according to the system configu-
ration and environmental considerations
inverter.ru (812) 702-47-50
VLT Refrigeration Drive FC 103 1.1-90 kW Operating Instructions

2.4.2.2 Grounding Using Shielded Cable

Earthing (grounding) clamps are provided for motor wiring
(see Illustration 2.7).
Illustration 2.7 Grounding with Shielded Cable

2.4.3 Access

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Device damage through contamination
Do not leave the frequency converter unconvered.
Illustration 2.8 Control Wiring Access for A2, A3, B3, B4, C3 and
C4 Enclosures
MG16E202 - VLT® is a registered Danfoss trademark
CAUTION
•
Remove access cover plate with a screw driver.
See Illustration 2.8.
•
Or remove front cover by loosening attaching
screws. See Illustration 2.9.
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