ABB ACQ810-04, Руководство по оборудованию, Страница: 44 / 144

44 Planning the electrical installation
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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 d u /d t filters protect motor insulation system and reduce bearing currents.
Common mode filters mainly reduce bearing currents. Insulated N-end (non-drive)
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 the hardware manual.
Checking the compatibility of the motor and drive
Use an AC induction motor with the drive. Several induction motors can be connected at a
time.
Select the motor and drive according to the rating tables in chapter Technical data. Use the
DriveSize PC tool if the default load cycles are not applicable.
1. Check that the motor ratings lie within the allowed ranges of the drive control program:
•
motor nominal voltage is in the range of 1/2...2 · U
N
•
motor nominal current is 1/3 ... 1 · I
max
of the drive in DTC control and
0 ... 1 · I
max
in scalar control. The control mode is selected by a control program
parameter.
2. Consult the motor manufacturer before using a motor in a drive system where the
motor nominal voltage differs from the AC power source voltage.
3. Ensure that the motor insulation system withstands the maximum peak voltage in the
motor terminals. See the Requirements table below for the required motor insulation
system and drive filtering.
Example 1: When the supply voltage is 440 V and the drive is operating in the motor
mode only, the maximum peak voltage in the motor terminals can be approximated as
follows: 440 V · 1.35 · 2 = 1190 V. Check that the motor insulation system withstands
this voltage.