Automation Direct Stellar SR55 Series, User Manual

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Page C–4 Stellar
®
SR55 Series Soft Starter User Manual – 1st Ed, Rev F – 09/18/2019
Appendix C: Electromagnetic Compatibility
c.7 – b
AsIc
emc c
oNsIdeRATIoNs
C.7.1 – i
mmuniTy
The product standard for immunity requirements is EN 60947-4-2:2012. All SR55 Soft Starter
products meet, or exceed the industrial level immunity requirements laid down in this
standard.
C.7.2 – e
missions
Emissions are classified as low frequency (below 9kHz), known as harmonics, and high or
radio frequency (above 9kHz). Both radio-frequency emissions and low-frequency harmonics
are generated by the action of the SR55 Soft-Starter.
NOTICE: This product has been designed for environment A. Use of this product in
environment B may cause unwanted electromagnetic disturbances in which case the user may
be required to take adequate mitigating measures.
C.7.3 – e
missions
- h
armoniCs
During normal operation, soft starters turn their semiconductor switches on and off in order
to vary the voltage at the motor terminals, and this introduces supply discontinuities and
generates harmonics. However, the mode of pulsing used by SR55 Soft Starters minimizes
these harmonic effects, since SR55 power circuits are configured as a fully-controlled
regulators (W3C).
Only non-triplen (integer multiples of the third harmonic), odd harmonic frequencies
are created, starting with and diminishing rapidly from the fifth harmonic, and virtually
disappearing by the nineteenth harmonic.
C.7.4 – e
missions
- r
adio
f
requenCy
(rf)
Radio frequency emissions are propagated in two ways:
1) Conduction along the leads supplying the soft starter.
2) Radiation from the operating equipment.
They also have two sources:
1) The high-frequency currents associated with the control electronics (this includes the
microprocessor).
2) The action of the semiconductor devices forming the power switching elements located
in the controller main circuits.
The radiation measurements made from operating versions of SR55 Soft Starters show levels
lower than the allowed limits. Further, enclosures of metallic construction provide additional
shielding for SR55 Soft Starters mounted within them. The only radiated interference effect
that might arise from a soft starter would be if mobile telephones, walkie-talkies, etc. were
to be used in very close proximity to a unit which was operating with the enclosure door
open. For this reason, any enclosure must display a label that brings the possibility of
electromagnetic interference to the attention of the operator under these circumstances.