Eaton PowerXL DM1 Series - Figure 5. Location of the EMC;MOV Screw in Frame 1; Figure 6. Location of the EMC;MOV Screws in Frames 2-4

10
Chapter 3—Engineering considerations
POWERXL SERIES VFDS MN040060EN—September 2020 www.eaton.com
Non-linear consumers (harmonics producers) include for
example:
•
Induction and arc furnaces, welding devices;
•
Current converters, rectifiers and inverters, soft starters,
variable frequency drives;
•
Switched-mode power supply units (computers, monitors,
lighting), uninterrupted power supply (UPS); and
•
The THD value (THD = Total Harmonic Distortion) is
defined in standard IEC/EN 61800-3 as the ratio of the
rms value of all harmonic components to the rms value
of the fundamental frequency. It is given in percent of the
total value.
The THD value of the harmonic distortion is stated in
relation to the rms value of the total signal as a percentage.
On a variable frequency drive, the total harmonic distortion
is greater than 100%.
To assist in the calculation of system harmonics, a Harmonic
Estimation Calculator Tool is available at
www.eaton.com/drives.
Reactive power compensation devices
Special compensation measures on the power supply side
is not required for PowerXL Series drives, which take on
very little reactive power of the fundamental harmonics
from the AC power supply network (cosØ ~0.98).
In the AC power networks with non-choked reactive current
compensation devices, current deviations can enable parallel
resonance and undefinable circumstances.
In the project planning for the connection of frequency
inverters to AC power networks with undefined
circumstances, please consider using AC chokes.
Installation in corner-grounded network and IT system
Corner grounded and IT system are allowed for all the drive
types.
In these circumstances the EMC protection class must be
changed to level C4. This is done by removing the built-in
EMC/MOV screws with a simple procedure described as
follows.
Remove the main cover of the AC drive and remove
the EMC/MOV screws depending on frame size (see
Figure 5–Figure 6). Once the screw is removed, it can be
reconnected to re-engage the EMC protection.
Figure 5. Location of the EMC/MOV screw in frame 1.
Figure 6. Location of the EMC/MOV screws in
frames 2-4.
EMC screw
MOV screw
EMC screw
MOV screw