Engineering
M-Max Series Adjustable Frequency Drive
MN04020003E—October 2013 www.eaton.com
21
Safety and Switching
Fuses and Cable Cross-Sections
The fuses and wire cross-sections allocated for power-side
connections depend on the rated input current I
LN
of the
frequency inverter (without input reactor).
CAUTION
When selecting the cable cross-section, take the voltage
drop under load conditions into account.
The consideration of other standards (for example, VDE 0113
or VDE 0289) is the responsibility of the user.
The national and regional standards (for example VDE 0113,
EN 60204) must be observed and the necessary approvals
(for example UL) at the site of installation must be fulfilled.
When the device is operated in a UL-approved system, use
only UL-approved breakers, fuses, fuse bases, and cables.
The leakage currents to ground (to EN 50178) are greater
than 3.5 mA. The connection terminals marked PE and the
housing must be connected with the ground circuit.
The leakage currents for the individual performance variables
are listed on
Page 142
.
CAUTION
The specified minimum PE conductor cross-sections
(EN 50178, VDE 0160) must be maintained.
Choose the cross-section of the PE conductor in the motor
lines at least as large as the cross-section of the phase lines
(U, V, W).
Cables and Fuses
The cross-sections of the cables and line protection fuses
used must correspond with local standards.
For an installation in accordance with UL guidelines, the
fuses and copper cable that are UL-approved and have a
heat-resistance of 140° to 167°F (60° to 75°C) are to be used.
Use power cables with insulation according to the specified
input voltages for the permanent installation. A shielded
cable is not required on the input side.
A completely (360°) shielded low impedance cable is
required on the motor side. The length of the motor cable
depends on the RFI class and must not exceed 98 ft (30m)
for the M-Max.
Residual-Current Device (RCD)
RCD (Residual Current Device): Residual current device,
residual current circuit breaker (FI circuit breaker).
Residual current circuit breakers protect persons and animals
from the existence (not the origination) of impermissibly high
contact voltages. They prevent dangerous, and in some
cases deadly injuries caused by electrical accidents, and also
serve as fire prevention.
WARNING
With frequency inverters, only AC/DC sensitive residual
current circuit breakers (RCD type B) are to be used
(EN 50178, IEC 755).
Identification on the Residual-Current Circuit-Breakers
Frequency inverters work internally with rectified AC
currents. If an error occurs, the DC currents can block a type
A RCD circuit breaker from triggering and therefore disable
the protective functionality.
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 noise 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 pulse frequency (switching frequency of the
inverter)
●
design of the noise filter
●
grounding measures at the site of the motor
AC/DC sensitive
(RCD, type B)
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