4.6.4 RFI Switch
Line power supply isolated from ground
If the adjustable frequency drive is supplied from an isolated line power source ( IT line power, floating delta and grounded delta) or TT/TN-S line power
with grounded leg, the RFI switch is recommended to be turned off (OFF)
1)
via par. 14-50
RFI Filter
on the drive and par. 14-50
RFI Filter
on the filter.
For further reference, see IEC 364-3. If optimum EMC performance is needed, parallel motors are connected or the motor cable length is above 82 ft [25
m], it is recommended to set par. 14-50
RFI Filter
to [ON].
1)
Not available for 525–600/690 V adjustable frequency drives in frame sizes D, E and F.
In OFF, the internal RFI capacities (filter capacitors) between the chassis and the intermediate circuit are cut off to avoid damage to the intermediate
circuit and to reduce the ground capacity currents (according to IEC 61800-3).
Please also refer to the application note
VLT on IT line power, MN.90.CX.02.
It is important to use isolation monitors that are capable for use together
with power electronics (IEC 61557-8).
4.6.5 Torque
When tightening all electrical connections, it is very important to tighten
with the correct torque. Too low or too high torque results in a bad elec-
trical connection. Use a torque wrench to ensure correct torque.
Figure 4.33: Always use a torque wrench to tighten the
bolts.
Frame size
Terminal
Torque
Bolt size
D
Line power
Motor
19–40 Nm (168–354 in-lbs)
M10
Load sharing
Brake
8.5–20.5 Nm (75–181 in-lbs)
M8
E
Line power
Motor
Load sharing
19–40 Nm (168–354 in-lbs)
M10
Brake
8.5–20.5 Nm (75–181 in-lbs)
M8
F
Line power
Motor
19–40 Nm (168–354 in-lbs)
M10
Load sharing
Brake
Regen
19–40 Nm (168–354 in-lbs)
8.5–20.5 Nm (75–181 in-lbs)
8.5–20.5 Nm (75–181 in-lbs)
M10
M8
M8
Table 4.2: Torque for terminals
VLT AQUA Low Harmonic Drive Instruction
Manual
4 How to Install
MG.20.T1.22 - VLT
®
is a registered Danfoss trademark
4-43
4
