Planning the electrical installation
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3ADW000462R0401 DCS880 Hardware manual e d
Monitoring the DCS880 power section
The power part of converters size H1 ... H6 is monitored by means of a galvanic isolated PTC
thermistor. The PTC is installed on the heat sink in an isolated configuration. The PTC's resistance
and protective effect correspond to the maximum temperature defined by the type code.
The air entry temperature at the power part of converters size H7 and H8 is monitored by means of a
galvanic isolated PTC thermistor. The sensor measures the power part's radiated heat and any
changes in the cooling air temperature and volume.
The PTC‘s resistance change is proportional to the temperature. It is read and evaluated in the
drive's firmware. If the temperature increases above the preset value, then first a warning and - if the
temperature continues to rise - a fault message is generated. The preset value must not be set more
than 5 degrees above the permissible ambient temperature.
For converter size H7 and H8 the cooling air volume can only be detected indirectly. Thus,
additionally a differential-pressure switch has been installed at the unit's housing. It is always located
close to the power terminals.
The differential-pressure switch compares the pressure inside the drive with the normal air pressure.
If the fan is switched on, the drive's door is closed, no covers have been removed and the pressure
switch signals 'cooling conditions ok' it is possible to release the converter. There is no need to set a
specific differential pressure (recommendation: use the center setting). The differential pressure
switch should be connected to the converter fan acknowledge signal.
Implementing thermal overload and short-circuit protection
Protecting
drive and input power cables in case of short-circuits
Protect drive and input cables using fuses as follows:
Size the fuses at the distribution board according to instructions given in chapter
. The fuses will
protect the input cables in short-circuit situations, restrict drive damage and prevent damage to adjoining
equipment in case of a short-circuit inside the drive.
Circuit breakers
The protective characteristics of circuit breakers depend on their type, construction and settings. There are also
limitations regarding to the short-circuit capacity of the supply network. Your local ABB representative can help
you in selecting the breaker type when the supply network characteristics are known.
WARNING
Due to the inherent operating principle and construction of circuit breakers, independent of the manufacturer,
hot ionized gases can escape from the breaker enclosure in case of a short-circuit. To ensure safe use, pay
special attention to the installation and placement of the breakers. Obey the manufacturer’s instructions.
Protecting
the motor and motor cable in case of short-circuits
The drive protects the motor cables and motor in a short-circuit situation when the motor cables are sized
according to the nominal current of the drive. No additional protection devices are needed.
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