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46 Planning the electrical installation
Motor selection and compatibility
1.
Select the motor according to the rating tables in
the DriveSize PC tool if the default load cycles are not applicable.
2. Check that the motor ratings lie within the allowed ranges of the drive control
program:
•
motor nominal voltage is 1/2 ... 2 ·
•
motor nominal current is 1/6 ... 2 ·
I
0 ... 2 ·
in scalar control. The control mode is selected by a drive parameter.
2hd
3. Check that the motor voltage rating meets the application requirements:
If the drive has ...
IGBT supply
ACS800-31/U31
U
= Rated input voltage of the drive
N
U
U
=
/1.41
ACeq2
DC
U
= the maximum DC link voltage of the drive in VDC.
DC
For resistor braking:
For units with IGBT supply: See the parameter value.
Note: Nominal DC link voltage is (in VDC):
U
× 1.35 when the IGBT supply is stopped or
N
U
× 1.41 when the IGBT supply is on.
N
See notes 7 and 8 below the
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.
5. Ensure that the motor insulation system withstands the maximum peak voltage
in the motor terminals. See the
required motor insulation system and drive filtering.
Example 1: When the supply voltage is 440 V and a drive with a diode supply is
operating in 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.
Example 2: When the supply voltage is 440 V and the drive has an IGBT supply,
the maximum peak voltage in the motor terminals can be approximated as
follows: 440 V · 1.41 · 2 = 1241 V. Check that the motor insulation system
withstands this voltage.
Protecting the motor insulation and bearings
The output of the drive comprises – regardless of output frequency – pulses of
approximately 1.35 times the equivalent mains network voltage with a very short rise
time. This is the case with all drives employing modern IGBT inverter technology.
The voltage of the pulses can be almost double at the motor terminals, depending
on the attenuation and reflection properties of the motor cable and the terminals.
This in turn can cause additional stress on the motor and motor cable insulation.
U
of the drive
N
I
of the drive in DTC control and
2hd
... and ...
DC link voltage is not increased from
nominal (parameter setting)
DC link voltage is increased from
nominal (parameter setting)
U
= 1.21 × nominal DC link voltage.
DC
Requirements table
Requirements table
Technical data
(page 119). Use
... then the motor voltage
rating should be ...
U
N
U
ACeq2
.
(page 48)
(page 48) below for the
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