Automationdirect.com Stellar SR44, Руководство пользователя

Страница: 72 / 238

Chapter 4: Electromagnetic Compatibility
4.7.7 – Strategies for Attaining and Maintaining EMC Compliance
Where possible, minimize the effect of electrical interference by using the strategies listed below.
• Locate the SR44 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 SR44 are opto-isolated,
and do not normally require buffering (e.g. through a small relay) or shielding.
Compliance in residential environments (Equipment class B) can be achieved by one of the
following two methods:
a) Bypassing the soft starter with an AC1 rated contactor controlled by the programmable relay set to
the 'top-of-ramp'. (The ramp-up and ramp-down features remain effective in this configuration)
b) By running the soft starter in phase loss only mode.
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 SR44 controller and motor are considered
to be an extension of the enclosure, and preferably should be contained within grounded metallic
trucking 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.
An alternative method of achieving the residential environment EMC requirements is to insert a
special purpose filter designed for use with variable-frequency drives. Care must be taken to
ensure that the short-term current rating of the filter will allow for the starting currents
experienced. If this method is adopted, it is essential that the motor/controller connections are
kept within 10 meters.
All associated electrical and electronic equipment near to the controller complies with the
emission and immunity requirements of the EMC Directive.
SR44 Series Soft Starter User Manual
1st Ed, Rev B 07/31/2019
4–6