Power Circuits - AuCom MVE Series User Manual

INSTALLATION
5.3

Power Circuits

Overview
MVE soft starters are designed to operate as part of a system including other components.
• A bypass switching device (contactor or vacuum circuit breaker) is required in all installations.
A main switching device (contactor or circuit breaker) is required in all installations. This can be located
•
in the soft starter panel or the upstream feeder panel.
If contactors are used for one or both switching devices, appropriately rated fuses must be installed
•
upstream of the main switching device to provide short circuit protection if the short circuit level of the
network/supply is higher than the short circuit rating of the contactor.
Additional components may also be required to comply with soft starter panel specifications.
Main Switching Device
The MVE can be installed with a main contactor or a circuit breaker.
• Select a contactor with an AC3 rating greater than or equal to the full load current rating of the
connected motor.
Select a circuit breaker greater than or equal to the full load current rating of the connected motor.
•
The main switching device is associated with terminals L1, L2, L3 on the supply side of the soft starter. The coil is
associated with output terminals 13, 14 of the MVE.
To ensure that the potentially dangerous medium voltage area is isolated from the low voltage control area, power is
supplied to the main switching device coil from the control voltage terminal block.
Bypass Switching Device
The MVE must always be installed with a bypass contactor or circuit breaker.
• Select a contactor with an AC3 rating greater than or equal to the full load current rating of the
connected motor.
Select a circuit breaker greater than or equal to the full load current rating of the connected motor.
•
The bypass switching device is associated with terminals L1, L2, L3 on the supply side of the soft starter, and bypass
terminals T1B, T2B, T3B on the motor side. The coil is associated with output terminals 23, 24, and the auxiliary
Normally Open contact is associated with input terminals C73, C74 of the soft starter.
To ensure that the potentially dangerous medium voltage area is isolated from the low voltage control area, power is
supplied to the bypass switching device coil from the control voltage terminal block.
R Rated Protection Fuses
If contactors are used for one or both switching devices, appropriately rated fuses must be installed upstream of the
main switching device to provide short circuit protection if the short circuit level of the network/supply is higher than
the short circuit rating of the contactor. Select the appropriate fuse based on the motor's rated full load current.
Transient/ Overvoltage Protection
Overvoltage protection should be installed if there is a risk of high voltage transients at the installation. Contact your
local supplier for details.
Line Inductors
Output line inductors may be required depending on various factors, including the soft starter model, the system
operating voltage, the cable type, and the length of the cable run between the soft starter and the motor.
If required, line inductors are typically installed in a shielded caged enclosure at the soft starter end of the motor
cable.
To find out if line inductors are required for your specific installation, contact your local supplier for advice. You will
need to provide information about the motor output cable, including the cable length, cable type, and cable inductance
and capacitance per km.
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