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Synergy Series Soft Start User Manual
MAN-SGY-017. Version 01. 27/06/2016
196
In the case of an isolated or high impedance grounded system, seek advice from your supplier before
fitting a capacitive high frequency filter to an Synergy Soft Starter. It is essential that the specifying
authority, user, or installer has a clear knowledge of the type of network to which the product is to be
installed before making decisions as to which EMC strategy to adopt.
As supplied, all Synergy products comply with the conducted emissions requirements for
environment class A as defined by EN 60947-4-2:2012 Table 19. However, the length and type of
cable connecting the motor to the starter module materially affects the level of emissions
generated, and can amplify them greatly. The standard also allows different levels of emissions
depending on rated input power, which also affects the need to fit filters. The EN 60947-4-2:2012
standard only requires consideration of steady-state conditions for EMC emission purposes, and
expressly excludes varying conditions such as those during ramp-up and ramp-down.
Finally, statistics show that the number of disturbances arising from soft starters, operating in a
very wide variety of applications and networks throughout the world, is insignificant. Where
EMC disturbances occur, it is very unlikely that they can be genuinely attributed to a soft starter.
9.7.7 Strategies for Attaining and Maintaining EMC Compliance
Where possible, minimize the effect of electrical interference by using the strategies listed below.
•
Locate the Synergy Soft Starter unit as close as reasonably possible to the motor terminal box in
order to minimize cable length.
•
Ensure that, within any enclosure, the control wiring does not run parallel to the power wiring.
Where this is unavoidable, maintain a 100 mm [3.9 in] separation between control cables and
power cables.
• Where possible, ensure that the control wiring crosses at right angles to the power wiring. This
practice reduces the cross-coupling between cables.
•
Shield any cables carrying sensitive signals. The digital control inputs to a Synergy are
opto-isolated, and do not normally require buffering (e.g. through a small relay) or shielding.
Where a special purpose system filter has been applied at the point of common coupling, additional
filtering of individual drives is not necessary and may introduce undesirable effects due to resonance.
For the purposes of EMC, the connections between the Synergy controller and motor are considered to
be an extension of the enclosure, and preferably should be contained within grounded metallic trunking
or conduit. Armored cable may be used providing it is correctly terminated, although the EMC
performance will be slightly inferior. Shielded cable is not necessary.
All associated electrical and electronic equipment near to the controller complies with the
emission and immunity requirements of the EMC Directive.
9. EMC (continued)