Operating Speed; Dimensioning The Motor For Variable Speed Application; General; Dimensioning With Abb Acs800 Converters With Dtc Control - ABB ACS800 Serie Manuel D'installation

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NOTE!
Proper cable glands providing 360° bonding must be
used at all termination points, e.g. at motor, convert-
er, possible safety switch, etc.
For motors of frame size IEC 280 and upward, addi-
tional potential equalization between the motor frame
and the driven equipment is needed, unless both are
mounted on a common steel base. In this case, the high
frequency conductivity of the connection provided by
the steel base should be checked by, for example,
measuring the potential difference between the compo-
nents.
More information about grounding and cabling of
variable speed drives can be found in the manual
"Grounding and cabling of the drive system" (Code:
3AFY 61201998).

5.7 Operating speed

For speeds higher than the nominal speed stated on
the motor's rating plate, ensure that either the highest
permissible rotational speed of the motor or the critical
speed of the whole application is not exceeded.
5.8 Dimensioning the motor for
variable speed application

5.8.1 General

In the case of ABB ACS800 converters with DTC
control, the dimensioning can be done by using the
loadability curves shown in paragraph 5.8.2 or by using
ABB's DriveSize dimensioning program. The tool is
downloadable from the ABB website (www.abb.com/
motors&drives). The loadability curves are based on
nominal supply voltage.
5.8.2 Dimensioning with ABB
ACS800 converters with DTC
control
The loadability curves (or load capacity curves) present-
ed in Figures 5 and 6 show the maximum allowed
continuous output torque of the motors as a function of
supply frequency. The output torque is given as a
percentage of the nominal torque of the motor.
NOTE!
The maximum speed of the motor must not be
exceeded even if the loadability curves are given up
to 100 Hz.
For dimensioning motors and protection types other
than those mentioned in Figures 5 and 6, please con-
tact ABB.
EN – 14
5.8.3 Dimensioning with other
voltage source PWM-type
converters
Preliminary dimensioning can be done by using follow-
ing guideline loadability curves, see Figures 7 and 8.
These guideline curves assume a minimum switching
frequency of 3 kHz. To ensure safety, the combination
must either be tested or thermal sensors intended for
control of the surface temperatures must be used.
NOTE!
The actual thermal loadability of a motor may be
lower than shown by guideline curves.

5.8.4 Short time overloads

ABB fl ameproof motors usually provide a possibility for
short time overloading. For exact values, please see the
motor's rating plate.
Overloadability is specifi ed by three factors:
I
Maximum short time current
OL
T
The length of allowed overload period
OL
T
Cooling time required after each overload
COOL
period. During the cooling period motor current
and torque must stay below the limit of allowed
continuous loadability.

5.9 Rating plates

The following parameters must be shown on the rating
plates of hazardous area motors intended for variable
speed operation:
– speed range
– power range
– voltage and current range
– type of torque (constant or quadratic)
– converter type and required minimum switching
frequency
5.10 Commissioning the
variable speed application
The commissioning of the variable speed application
must be done according to the instructions for the
frequency converter and local laws and regulations.
The requirements and limitations set by the application
must also be taken into account.
All parameters needed for setting the converter must be
taken from the motor rating plates. The most often
needed parameters are:
– Motor nominal voltage
– Motor nominal current
– Motor nominal frequency
– Motor nominal speed
– Motor nominal power
Note: In case of missing or inaccurate information, do
not operate the motor before ensuring correct settings!
ABB/Low Voltage Motors/ Ex manual 01-2007

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