Danfoss iC2-Micro Series - EMC Compatibility and Motor Cable Length; Du;Dt Conditions

Design Guide | iC2-Micro Frequency Converters Specifications
4.7 EMC Compatibility and Motor Cable Length
l Drive with built-in EMC filter fulfills radiated emission C2 limits.
l Drive with non built-in EMC filter fulfills conducted/radiated emission C4 requirements.
l The drive is designed to operate with optimum performance within the maximum motor cable lengths defined in Table 38.
Table 37: EMC Compatibility Motor Cable Length
Maximum motor cable length (shielded), @4kHzDrive with built-in EMC filter
C1 (Conducted) C2 (Conducted)
1x200–240V 5m (16.4ft) –
3x400–480V – 15m (49.2ft)
Table 38: Maximum Motor Cable Length
Maximum motor cable length (shielded) Maximum motor cable length (unshielded)
50m (164ft) 75m (246ft)
4.8 dU/dt Conditions
When a transistor in the drive bridge switches, the voltage across the motor increases by a dU/dt ratio depending on the following
factors:
l The motor cable type.
l The cross-section of the motor cable.
l The length of the motor cable.
l Whether the motor cable is shielded or not.
l Inductance.
The natural induction causes an overshoot U
PEAK
in the motor voltage before it stabilizes itself at a level depending on the voltage in the
DC link. The rise time and the peak voltage U
PEAK
affect the service life of the motor.
If the peak voltage is too high, motors without phase coil insulation are affected. The longer the motor cable, the higher the rise time and
peak voltage.
Switching of the IGBTs causes peak voltage on the motor terminals. The iC2-Micro Frequency Converterscomply with IEC 60034-25
regarding motors designed to be controlled by drives. The iC2-Micro Frequency Converters also comply with IEC 60034-17 regarding
Norm motors controlled by drives.
The following dU/dt data are measured at the motor terminal side with IEC 50% torque:
Table 39: dU/dt Data for iC2-Micro Frequency Converters
Enclosure size Power [kW(hp)] Cable length
[m(ft)]
Mains voltage
[V]
Rise time [μ
sec
] U
PEAK
[kV] dU/dt [kV/μ
sec
]
MA01c 0.37 (0.5) 5 (16.4) 1x120 0.067 0.438 5.21
MA01c 0.37 (0.5) 50 (164) 1x120 0.286 0.618 1.73
MA01c 0.75 (1.0) 5 (16.4) 1x240 0.067 0.438 5.21
MA01c 0.75 (1.0) 50 (164) 1x240 0.286 0.618 1.73
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