Specifications

Ensure that the impedance from frequency
converter to building ground is lower than the
grounding impedance of the machine. Make a
direct earth connection between the motor and
load motor
•
Apply conductive lubrication
•
Try to ensure that the line voltage is balanced to
ground. This can be difficult for IT, TT, TN-CS or
Grounded leg systems
•
Use an insulated bearing as recommended by the
motor manufacturer
NOTICE
Motors from reputable manufacturers will typically have
these fitted as standard in motors of this size.
If none of these strategies works, consult the factory.
If necessary after consulting Danfoss:
•
Lower the IGBT switching frequency
•
Modify the inverter waveform, 60° AVM vs.
SFAVM
•
Install a shaft grounding system or use an
isolating coupling between motor and load
•
Use minimum speed settings if possible
•
Use a dU/dt or sinus filter
5.5 Installation of Misc. Connections
5.5.1 RS-485 Bus Connection
One or more frequency converters can be connected to a
control (or master) using the RS-485 standardized interface.
Terminal 68 is connected to the P signal (TX+, RX+), while
terminal 69 is connected to the N signal (TX-, RX-).
If more than one frequency converter is connected to a
master, use parallel connections.
130BA060.11
68 69 68 69 68 69
RS 485
RS 232
USB
+
-
Illustration 5.101 RS-485 Connecting Multiple Frequency
Converters to Master
In order to avoid potential equalizing currents in the
screen, earth the cable screen via terminal 61, which is
connected to the frame via an RC-link.
For EMC correct installation, refer to 5.7 EMC-correct Instal-
lation.
Bus termination
The RS-485 bus must be terminated by a resistor network
at both ends. Set switch S801 on the control card for "ON".
For more information, see 5.2.16 Switches S201, S202, and
S801.
Communication protocol must be set to 8-30 Protocol.
5.5.2 How to Connect a PC to the
Frequency Converter
To control or program the frequency converter from a PC,
install the PC-based configuration tool MCT 10 Set-up
Software.
The PC is connected via a standard (host/device) USB
cable, or via the RS-485 interface as shown in 5.5.1 RS-485
Bus Connection.
NOTICE
The USB connection is galvanically isolated from the
supply voltage (PELV) and other high-voltage terminals.
The USB connection is connected to protection earth.
Use only an isolated laptop as PC connection to the USB
connector on the frequency converter.
130BT308.10
Illustration 5.102 For Control Cable Connections, See 5.2.11
Control Terminals
PC-based Configuration Tool MCT 10 Set-up Software
All frequency converters are equipped with a serial
communication port. Danfoss provides a PC tool for
communication between PC and frequency converter, PC-
based configuration tool MCT 10 Set-up Software.
MCT 10 Set-up Software
MCT 10 Set-up Software has been designed as an easy to
use interactive tool for setting parameters.
How to Install VLT® HVAC Drive FC 102 Design Guide
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