Installation Of Softstarters Type Psd(H) In Public Network - ABB PS D75 840 Series Installation And Maintenance Instruction

Installation of Softstarters type PSD(H) in public network:

In softstarters PSD(H) thyristors and microprocessors are used that can cause
emission/disturbances during operation. In public network the requirements only allow for low
emission levels. In order to fulfil this requirement some actions must be taken.
Mounted in any metal enclosure with a by-pass contactor and using screened cables outside the
enclosure the system fulfils the compatibility requirement. Another advantage by using a by-pass
contactor is that the total powerloss is reduced, and thus it is not needed to have extra fans for
cooling.
Below you will find closer description of each action;
• By-pass contactor: When a by-pass contactor is used the softstarter is by-passed at continuous
operation, The by-pass contactor is connected in parallel to the softstarter that is only active during
start and stop of the motor. The operation is simplified if the built in signal relay K5 (top of ramp /
TOR) is used to control the by-pass contactor. The by-pass contactor is automatically in operation
after completed start and will remain so during continuous operation. The Softstarter can still be in
active status but no current will pass through it, instead all current will pass through the by-pass
contactor.
For connection of the by-pass contactor, please see section 2.
• Function PF (Energy saving at low motor load): can not be activated during operation with a by-
pass contactor included.
• Earthing: The Softstarter has to be connected to earth.
• Enclosure: Use any type of metal enclosure. Our recommendation is that you ensure that all
details like door, box and assembly plate have a good earthing.
• Cables:
-Control cables : Use so called pair twisted signal cable where the connections are to be made to
the softstarter. This type of cable always has a screen that shall be connected to earth.
-Power cables: Use a collectively (360º) screened / shielded power cable for feeding the motor,
and when the softstarter is installed in a separate enclosure, also for the cable feeding the
softstarter. Ensure that the screen is connected to earth. It is not necessary to use a special high
frequency screened cable. Any type of conducting screen will do.
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