Electrical Installation Of Motor Compressor Cables; Compressor Motor Protection; Access To Control Terminals - Danfoss VLT CDS 303 Operating Instructions Manual

How to Install
3.3.7 Electrical Installation of Motor
Compressor Cables
Screening of cables
Avoid installation with twisted screen ends (pigtails). They
reduce the screening effect at higher frequencies.
Cable length and cross section
The frequency converter has been tested with a given
length of cable and a given cross section of that cable. If
the cross section is increased, the cable capacitance - and
thus the leakage current - may increase, and the cable
length must be reduced correspondingly.
Aluminum conductors
Aluminium conductors are not recommended. Terminals
accept aluminium conductors, but clean the conductor
surface and remove and seal the oxidation by neutral acid-
free Vaseline grease before the conductor is connected.
Furthermore, the terminal screw must be retightened after
two days due to the softness of the aluminium. It is crucial
to keep the connection a gas tight joint, otherwise the
aluminium surface oxidizes again.

3.3.8 Compressor Motor Protection

The frequency converter fully provides electrical
compressor motor protection.
•
The frequency converter makes through an
electronic current measurement anti-overload and
lock-rotor compressor motor protection (see
description in the application manual).
•
The frequency converter is protected against
short circuits on compressor terminals T1, T2, T3
•
If a mains phase is missing, the frequency
converter trips or issues a warning (depending on
the load)
•
If a compressor motor phase is missing, the
frequency converter trips
•
The frequency converter is protected against
ground faults on compressor motor terminals T1,
T2, T3
MG34M422
Operating Instructions

3.3.9 Access to Control Terminals

Figure 3.16 B3, B4 and C3 Enclosures
Figure 3.17 C1, B1 and B2 Enclosures
Control terminals are located beneath the LCP. The inside
of the removable cover shows the terminals.
Danfoss A/S © Rev. 2013-07-03 All rights reserved.
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