Eaton PowerXL DH1 - Leakage Current; Input Contactor

23
Chapter 4—Safety and switching
POWERXL SERIES VFD MN040002EN—February 2018 www.eaton.com
CAUTION
Debounced inputs may not be used in the safety
circuitdiagram.
Residual current circuit breakers (RCD) are only to be
installed between the AC power supply network and the
frequency inverter.
Safety-relevant leakage currents can occur while handling
and when operating the frequency inverter, if the frequency
inverter is not grounded (because of a fault).
Leakage currents to ground are mainly caused by foreign
capacities with frequency inverters, between the motor
phases and the shielding of the motor cable and via the
Y-capacitors of the RFI filter. The size of the leakage current
is mainly dependent upon the:
•
length of the motor cable
•
shielding of the motor cable
•
height of the switching frequency of the inverter
•
design of the RFI filter
•
grounding measures at the site of the motor
The leakage current to ground is greater than 3.5 mA
with afrequency inverter. According to product standard
IEC/EN 61800-5-1, an additional equipment grounding (PE)
conductor of the same cross-sectional area as the original
protective earthing conductor should be connected, or the
cross-section of the equipment grounding conductor should
be at least 10
mm
2
Cu.
Residual current circuit breakers must be suitable for:
•
the protection of installations with DC current component
in case of fault scenario (RCD type B)
•
high leakage currents
•
brief discharges of pulse current spikes
Leakage current
CAUTION
As shown in Table 16 below, the following leakage
currents were detected. These values were obtained under
normal operating conditions with no outside influences.
Actual values will differ depending on the conditions
previouslyexplained.
Input contactor
The input contactor enables an operational switching on
and off of the supply voltage for the frequency inverter, and
switching off in case of a fault.
The input contactor is designed based on the input current
(ILN) of the frequency inverter and the utilization category
AC-1 (IEC 60947). Input contactors and the assignment to
PowerXL frequency inverters are explained in Appendix A.
While planning the project, make sure that inching operation
is not done via the input contactor of the frequency inverter
on frequency-controlled drives, but through a controller
input of the frequency inverter.
The maximum permitted operating frequency of the input
voltage with the PowerXL frequency inverter is one time per
minute (normal operation).