Selection Of Winding Insulation With All Other Converters; Thermal Protection Of Windings; Bearing Currents; Elimination Of Bearing Currents With Abb Acs800 Converters - ABB M2A Manual De Instalación E Usuario

Nominal supply
voltage U of
N
the converter Winding insulation and filters required
≤ 500 V
U ABB Standard insulation
N
≤ 600 V
U ABB Standard insulation + dU/dt filters
N
OR
ABB Special insulation
(variant code 405)
≤ 690 V
U ABB Special insulation
N
(variant code 405)
AND
dU/dt-filters at converter output
For more information on resistor braking and converters
with controlled supply units, please contact ABB.
5.3.4 Selection of winding insulation
with all other converters
The voltage stresses must be limited below accepted
limits. Please contact the system designer to ensure the
safety of the application. The influence of possible filters
must be taken into account while dimensioning the motor.
5.4 Thermal protection of
windings
All cast iron ABB Ex motors are equipped with PTC
thermistors to prevent the winding temperatures from
exceeding the thermal limits of used insulation materials
(usually Insulation Class B or F).
NOTE!
If not otherwise indicated on the rating plate, these
thermistors do not prevent motor surface temperatures
exceeding the limit values of their temperature classes
(T4, T5, etc.).
ATEX-countries:
The thermistors must be connected to a thermistor circuit
relay functioning independently and that is dedicated to
reliably trip off the supply to the motor according to the
requirements of the "Essential Health and Safety Require-
ments" in Annex II, item 1.5.1 of the ATEX Directive 94/9/
EC.
Non-ATEX countries:
It is recommended that the thermistors are connected to a
thermistor circuit relay functioning independently and that
is dedicated to reliably trip off the supply to the motor.
NOTE!
According to the local installation rules, it may be
possible to also connect the thermistors to equipment
other than a thermistor relay; for example, to the control
inputs of a frequency converter.

5.5 Bearing currents

Bearing voltages and currents must be avoided in all
variable speed applications to ensure the reliability and
safety of the application. For this purpose insulated
bearings or bearing constructions, common mode filters
and suitable cabling and grounding methods must be
used.
5.5.1 Elimination of bearing currents
with ABB ACS800 converters
In the case of the ABB ACS800 frequency converter with a
diode supply unit (uncontrolled DC voltage), the following
methods must be used to avoid harmful bearing currents
in the motors:
Frame size
250 and smaller
280 – 315
355 – 450
ABB uses insulated bearings which have aluminum oxide
coated inner and/or outer bores or ceramic rolling ele-
ments. Aluminum oxide coatings are also 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.
5.5.2 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 5.5.1 can be followed, but their
effectiveness cannot be guaranteed in all cases.

5.6 Cabling, grounding and EMC

To provide proper grounding and to ensure compliance
with any applicable EMC requirements, motors above 30
kW must be cabled using shielded symmetrical cables and
EMC glands, i.e. cable glands providing 360° bonding.
Also for smaller motors symmetrical and shielded cables
are highly recommended. 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/
busbar inside the terminal box, converter cabinet, etc.
NOTE!
Proper cable glands providing 360° bonding must be
used at all termination points, e.g. at motor, converter,
possible safety switch, etc.
For motors of frame size IEC 280 and upward, 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
Low voltage Ex motor manual 01-2007 | ABB Motors and Generators EN – 13
No actions needed
Insulated non-drive end bearing
Insulated non-drive end bearing
AND
Common mode filter at the converter