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52 Planning the electrical installation
European Union
To meet the European Union Directives, according to standard EN 60204-1, Safety of
Machinery, the disconnecting device must be one of the following types:
•
switch-disconnector of utilization category AC-23B (EN 60947-3)
•
disconnector that has an auxiliary contact that in all cases causes switching devices to
break the load circuit before the opening of the main contacts of the disconnector
(EN 60947-3)
•
circuit breaker suitable for isolation in accordance with EN 60947-2.
Other regions
The disconnecting device must conform to the applicable safety regulations.
Selecting and dimensioning the main contactor
If a main contactor is used, its utilization category (number of operations under load) must
be AC-1 according to IEC 60947-4, Low-voltage switchgear and controlgear. Dimension
the main contactor according to the nominal voltage and current of the drive.
Protecting the motor insulation and bearings
The drive employs modern IGBT inverter technology. Regardless of frequency, the drive
output comprises pulses of approximately the drive DC bus voltage with a very short rise
time. The pulse voltage can almost double at the motor terminals, depending on the
attenuation and reflection properties of the motor cable and the terminals. This can cause
additional stress on the motor and motor cable insulation.
Modern variable speed drives with their fast rising voltage pulses and high switching
frequencies can generate current pulses that flow through the motor bearings, which can
gradually erode the bearing races and rolling elements.
Optional du/dt filters protect motor insulation system and reduce bearing currents.
Common mode filters mainly reduce bearing currents. insulated N-end (non-drive end)
bearings protect the motor bearings. See section Checking the compatibility of the motor
and drive below for the required filters and N-end bearings to be used with the drive.
Select and install the cables according to the instructions given in this manual.
Checking the compatibility of the motor and drive
Use an AC induction motor with the drive. Several induction motors can be connected to
the drive at a time.
Select the motor and drive according to the rating tables in chapter
1. Check that the motor ratings lie within the allowed ranges of the drive control program:
2. motor nominal voltage is in the range of 1/2 ... 2 · U
3. motor nominal current is 1/3 ... 1 · I
0 ... 1 · I
in scalar control. The control mode is selected by a drive parameter.
max
4. Consult the motor manufacturer before using a motor in a drive system where the
motor nominal voltage differs from the AC power source voltage.
N
of the drive in DTC control and
max
Technical
data.
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