Guidelines for planning the electrical installation 69
Implementing thermal overload and short-circuit
protection
Protecting the drive and input power cable in short-circuits
Protect the drive with fuses and the input cable with fuses or a circuit breaker with current
restriction.
Equip the fuses with blown fuse indicators for stopping the drive.
Size the fuses or the circuit breaker according to local regulations for the input cable
protection. Select the fuses for the drive according to the instructions given in chapter
Technical data. The fuses for the drive protection will 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 the type, construction and
settings of the breakers. There are also limitations pertaining 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 short-circuits
The drive protects the motor cable and motor in a short-circuit situation when the motor
cable is dimensioned according to the nominal current of the drive. No additional
protection devices are needed.
Protecting the drive and the input power and motor cables against
thermal overload
The drive protects itself and the motor cables against thermal overload when the cables
are dimensioned according to the nominal current of the drive. No additional thermal
protection devices are needed.
In 6-pulse connection with a common main circuit breaker, the drive protects the input
cables against thermal overload when the cables are dimensioned according to the
nominal current of the drive.
For 12-pulse connection and 6-pulse connection with individual circuit breakers, use gG
fuses with blown fuse indicators for the thermal protection of the input cables. Wire the
indicators to stop the drive in case of a blown fuse.
To Next Page
Loading...
