Residual Current Circuit-Breaker (Rcd); Mains Contactors - Eaton PowerXL DB1 Installation Manual

2.4.3 Residual current circuit-breaker (RCD)

2.4.4 Mains contactors

When using variable frequency drives (DB1-3...) that work with a three-
phase power supply (L1, L2, L3), ensure that only type Bfq AC/DC sensitive
residual current devices are used.
When using variable frequency drives that work with a single-phase power
supply (L, N) (DB1-12...), type F residual current devices (RCD) may be used.
ATTENTION
Residual-current devices (RCD) may only be installed between the
supply system (AC mains supply) and the DB1 variable frequency
drive – they must never be installed in the motor output.
The leakage currents' magnitude will generally depend on:
• the length of the motor cable,
• the shielding of the motor cable,
• the height of the switching frequency (switching frequency of the
inverter),
• the design of the radio interference suppression filter,
• the grounding measures at the site of the motor, and
• the symmetry of the supply system.
Other protective measures against direct and indirect contact can be used for
DB1 variable frequency drives, including isolating them from the supply sys-
tem with the use of a transformer.
A mains contactor enables operational switching on and off of the supply
voltage for the variable frequency drive and switching off in case of a fault.
The mains contactor is designed based on the mains-side input current I
the DB1 variable frequency drive for utilization category AC-1 (IEC 60947)
and the ambient temperature at the location of use.
￫
While planning the project, please make sure that inching opera-
tion is not done via the mains contactor of the variable fre-
quency drive on frequency-controlled drives, but through a con-
troller input of the variable frequency drive.
The mains voltage on the DB1 variable frequency drive can be
switched on a maximum of once every 30 seconds (normal
operation).
￫
For UL-compliant installation and during operation, the mains
side switching devices must allow for a 1.25 times higher input
current.
￫
For the rated mains contactors for DB1 variable frequency
drives, please refer to ￫ section 5.6, "Mains contactors",
page 84.
DB1 Variable Frequency Drives 09/17 MN040031EN www.eaton.com
2 Engineering
2.4 Safety and switching
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