Electromagnetic Compatibility (Emc) Overview - Danfoss VLT AQUA Drive FC 202 Design Manual

Electrical Installation Con...
525–690 V
Power size [kW (hp)] Cable [m (ft)]
450–630 (450–650)
710–800 (750–950)
Table 10.20 IEC dU/dt Test Results for E1h–E4h with Unshielded Cables and No Output Filter, 525–690 V
Power size [kW (hp)] Cable [m (ft)]
450–630 (450–650)
710–800 (750–950)
Table 10.21 IEC dU/dt Test Results for E1h–E4h with Shielded Cables and No Output Filter, 525–690 V
NOTICE
TEST RESULTS
NEMA does not provide dU/dt results for 690 V.

10.14 Electromagnetic Compatibility (EMC) Overview

Electrical devices both generate interference and are affected by interference from other generated sources. The electro-
magnetic compatibility (EMC) of these effects depends on the power and the harmonic characteristics of the devices.
Uncontrolled interaction between electrical devices in a system can degrade compatibility and impair reliable operation.
Interference takes the form of the following:
•
Electrostatic discharges
•
Rapid voltage fluctuations
•
High-frequency interference
Electrical interference is most commonly found at frequencies in the range 150 kHz to 30 MHz. Airborne interference from
the drive system in the range 30 MHz to 1 GHz is generated from the inverter, motor cable, and the motor.
Capacitive currents in the motor cable, coupled with a high dU/dt from the motor voltage, generate leakage currents. See
Illustration 10.16. Shielded motor cables have higher capacitance between the phase wires and the shield, and again
between the shield and ground. This added cable capacitance, along with other parasitic capacitance and motor inductance,
changes the electromagnetic emission signature produced by the unit. The change in electromagnetic emission signature
occurs mainly in emissions less than 5 MHz. Most of the leakage current (I1) is carried back to the unit through the PE (I3),
leaving only a small electromagnetic field (I4) from the shielded motor cable. The shield reduces the radiated interference
but increases the low-frequency interference on the mains.
MG22B102
Design Guide
Mains voltage
[V]
30 (98) 690
50 (164) 690
5 (16) 690
20 (65) 690
50 (164) 690
Mains voltage
[V]
5 (16) 690
48 (157) 690
150 (492) 690
5 (16) 690
48 (157) 690
150 (492) 690
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Rise time [µs] Peak voltage [V]
0.37 1625
0.86 2030
0.25 1212
0.33 1525
0.82 2040
Rise time [µs] Peak voltage [V]
0.23 1450
0.38 1637
0.94 1762
0.26 1262
0.46 1625
0.94 1710
dU/dt [V/µs]
3494
1895
3850
3712
1996
dU/dt [V/µs]
5217
3400
1502
3894
2826
1455
10 10
89