Elimination Of Bearing Currents With All Other Converters; Cabling, Grounding And Emc; Operating Speed; Motors In Variable Speed Applications - ABB MT Série Manuel D'installation, D'exploitation Et De Maintenance

NOTE!
Insulated bearings which have aluminum oxide
coated inner and/or outer bores or ceramic rolling
elements are recommended. Aluminum oxide
coatings shall also be treated with a sealant to
prevent dirt and humidity penetrating into the porous
coating. For the exact type of bearing insulation, see
the motor's rating plate. Changing the bearing type
or insulation method without ABB's permission is
prohibited.
6.4.2 Elimination of bearing currents with
all other converters
The user is responsible for protecting the motor and driven
equipment from harmful bearing currents. Instructions
described in chapter 6.4.1 can be used as guideline, but
their effectiveness cannot be guaranteed in all cases.

6.5 Cabling, grounding and EMC

To provide proper grounding and to ensure compliance
with any applicable EMC requirements, motors above
30 kW shall be cabled by shielded symmetrical cables and
EMC glands, i.e. cable glands providing 360° bonding.
Symmetrical and shielded cables are highly recommended
also for smaller motors. Make the 360° grounding
arrangement at all the cable entries as described in the
instructions for the glands. Twist the cable shields into
bundles and connect to the nearest ground terminal/bus
bar inside the terminal box, converter cabinet, etc.
NOTE!
Proper cable glands providing 360° bonding must
be used at all termination points such as motor,
converter, possible safety switch, etc.
For motors of frame size IEC 280 and above, additional
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 components.
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).

6.6 Operating speed

For speeds higher than the nominal speed stated on the
motor's rating plate or in the respective product catalog,
ensure that either the highest permissible rotational speed
of the motor or the critical speed of the whole application is
not exceeded.
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ABB Motors and Generators | Low voltage motors manual, 3GZF500730-85 Rev F 02-2015
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6.7 Motors in variable speed
applications

6.7.1 General

With ABB's frequency converters, the motors can be
dimensioned by using ABB's DriveSize dimensioning
program. The tool is downloadable from the ABB website
(www.abb.com/motors&generators).
For application supplied by other converters, the motors
must be dimensioned manually. For more information,
please contact ABB.
The loadability curves (or load capacity curves) are based
on nominal supply voltage. Operation in under or over
voltage conditions may influence on the performance of the
application.
6.7.2 Motor loadability with AC_8_ _ – series
of converters with DTC control
The loadability curves presented in Figures 5a - 5d are
valid for ABB AC_8_ _-series converters with uncontrolled
DC-voltage and DTC-control. The figures show the
approximate maximum 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. The values are indicative and exact values are
available on request.
NOTE!
The maximum speed of the motor and application
may not be exceeded!
6.7.3 Motor loadability with AC_5_ _ – series
of converter
The loadability curves presented in Figures 6a - 6d are
valid for AC_5_ _ -series converters. The figures show
the approximate maximum 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. The values are indicative and exact values are
available on request.
NOTE!
The maximum speed of the motor and application
may not be exceeded!
6.7.4 Motor loadability with other voltage
source PWM-type converters
For other converters, with uncontrolled DC voltage and
minimum switching frequency of 3 kHz (200...500 V), the
dimensioning instructions as mentioned in chapter 6.7.3
can be used as guidelines. However, it shall be noted that
the actual thermal loadability can also be lower. Please
contact the manufacturer of the converter or the system
supplier.
6/2/2015 6:44:25 PM