2 Engineering
2.3 Safety and switching
44 DA1 Variable Frequency Drives 11/16 MN04020005Z-EN www.eaton.com
2.3.4 Residual current circuit-breaker
When using variable frequency drives (DA1-3…) that work with a three-
phase power supply (L1, L2, L3), make sure to use type B AC/DC sensitive
residual current devices exclusively.
When using variable frequency drives that work with a single-phase power
supply (L, N) (DA1-12…), you may use type A and type B residual current
devices (RCD).
The leakage currents’ magnitude will generally depend on:
• length of the motor cable,
• shielding of the motor cable,
• height of the pulse frequency (switching frequency of the inverter),
• Design of the radio interference suppression filter
• grounding measures at the site of the motor.
Other protective measures against direct and indirect contact can be used for
DA1 variable frequency drives, including isolating them from the supply
system with the use of a transformer.
NOTICE
Residual current circuit-breakers (RCD = residual current device)
should
only be installed between
the power feed system
(the AC
supply system supplying power) and the DA1 variable frequency
drive – not at the output to the motor!
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