Switches S201, S202, And S801 - Danfoss FC 300 Design Manual

6. How to Install
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6.3.11. Electrical Installation of Motor Cables
Shielding of cables
Avoid installation with twisted shield ends (pigtails). They spoil the shielding effect at higher fre-
6 quencies.
If it is necessary to break the shield to install a motor isolator or motor contactor, the shield must
be continued at the lowest possible HF impedance.
Cable length and cross-section
The adjustable frequency drive 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, thereby requiring that the cable length is reduced accordingly.
Switching frequency
When adjustable frequency drives are used together with sine-wave filters to reduce the acoustic
noise from a motor, the switching frequency must be set according to the sine-wave filter in-
structions in par. 14-01.
Aluminum conductors
Aluminum conductors are not recommended. Terminals can accept aluminum conductors, but the
conductor surface has to be clean, oxidation must be removed, and the area must be sealed 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
aluminum. It is crucial to keep the connection a gas-tight joint, otherwise the aluminum surface
will oxidize again.

6.3.12. Switches S201, S202, and S801

Switches S201 (A53) and S202 (A54) are used to select a current (0-20 mA) or a voltage (-10 to
10 V) configuration for the analog input terminals 53 and 54, respectively.
Switch S801 (BUS TER.) can be used to enable termination on the RS-485 port (terminals 68 and
69).
See drawing
Default setting:
126
Keep the motor cable as short as possible to reduce the noise level and leakage currents.
Connect the motor cable shield to both the decoupling plate of the FC 300 and to the
metal cabinet of the motor.
Make the shield connections with the largest possible surface area (cable clamp). This is
done by using the supplied installation devices in the FC 300.
Avoid mounting with twisted shield ends (pigtails), which will spoil high frequency shield-
ing effects.
If it is necessary to split the shield to install a motor isolator or motor relay, the shield
must be continued with the lowest possible HF impedance.
Diagram showing all electrical terminals
S201 (A53) = OFF (voltage input)
S202 (A54) = OFF (voltage input)
MG.33.B9.22 - VLT
Electrical Installation.
in section
® is a registered Danfoss trademark.
FC 300 Design Guide