KSB Magnochem-Bloc, Installation & Operating Manual

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5 Installation at Site
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Magnochem-Bloc
NOTE
Monitoring systems can be connected to casing cover 161 and bearing bracket
lantern 344. When insulating the casing cover and bearing bracket lantern make
sure that the sensor connections and displays remain accessible. Also observe the
sensor manufacturer's specifications regarding the permissible ambient
temperature.
5.6 Electrical connection
DANGER
Electrical connection work by unqualified personnel
Risk of fatal injury due to electric shock!
▷ Always have the electrical connections installed by a trained and qualified
electrician.
▷ Observe regulations IEC 60364 and, for explosion-proof models, EN 60079.
WARNING
Incorrect connection to the mains
Damage to the mains network, short circuit!
▷ Observe the technical specifications of the local energy supply companies.
DOL starting For DOL start-up the three motor winding connections are wired in delta
configuration from the beginning. This means that the mains voltage U
n
is
immediately available at the motor which is not yet running, i.e. the entire starting
torque is available right from the beginning. The pump set will reach the operating
speed within a very short period of time.
Star-delta starting For star-delta start-up the motor is wired in star configuration for the period of time
set at the time relay. In this configuration a lower voltage is applied to the windings.
U
n U =
3
After the set period of time has elapsed the motor switches to the delta
configuration in which the mains voltage U
n
is applied.
CAUTION
Switchover between star and delta on three-phase motors with star-delta starting
takes too long.
Damage to the pump (set)!
▷ Keep switch-over intervals between star and delta as short as possible.
The Y time at the time relay in star-delta configuration is the run-up period of the
motor during the star configuration. The specified Y times should not be exceeded as
this would cause the motor to heat up.
Table 8: Time relay settings for star-delta starting:
Motor rating Y time to be set
≤ 30 kW Approx. 3 sec.
> 30 kW, <90 kW Approx. 5 sec.
Starting via frequency
inverter
When starting the motor via a frequency inverter the motor runs up via continuously
variable speed control. Use of a frequency inverter prevents extreme current peaks
and abrupt loads on mechanical machine parts.