2 Engineering
2.5 Motor and Application
DC1 Frequency Inverter 10/12 MN04020003Z-EN www.eaton.com 43
2.5.6 Connecting EX motors
The following aspects must be taken into account when connectinghazard-
ous location motors:
• The frequency inverter must be installed outside the EX area.
• All applicable industry-specific and country-specific regulations for haz-
ardous locations (ATEX 100a) must be complied with.
• The specifications and instructions provided by the motor’s manufac-
turer with regard to operation with a frequency inverter – e.g., whether
motor reactors (dV/dt limiting) or sinusoidal filters are required – must be
taken into account.
• Temperature monitors in the motor windings (thermistor, Thermo-Click)
must not be connected directly to the frequency inverter, but instead
must be connected through a relay approved for the hazardous location
(e.g. EMT6).
2.5.7 Sinusoidal filter
Sinusoidal filters are connected in the output of a frequency inverter.
Figure 17: Circuit Diagram of a sinusoidal filter
The sinusoidal filter removes high-frequency components above the set
resonance frequency from the frequency inverter output voltage (U
2
).
This reduces the conducted and radiated emission.
a Without sinusoidal filter
b With sinusoidal filter
f: Rotating field frequency
n: Order of harmonics
Figure 18: High frequency components of the output voltage
U
2
U ∼
1U2
1V2
1W2
PE
1U1
1V1
1W1
PE
M
3 ~
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