ARLA/CLUSTER: FCC clarifica que as emissões de RF da lâmpadas de Leds falham nas regras estabelecidas.

[João Costa > CT1FBF]

FCC's OET clarifies emissions compliance testing for RF LED lighting devices

The FCC's Office of Engineering and Technology (OET) has clarified that all
RF LED lighting devices falling under Part 15 rules as 'unintentional
radiators' must meet conducted and radiated emissions limits set forth in
those rules.

"Operation of Part 15 unintentional radiators is subject to the condition
that no harmful interference is caused," the OET reminded, in a knowledge
database paper released on June 17. "Manufacturers and users should
therefore note that lighting devices are required to cease operation, if
harmful interference occurs."

The OET said radiated emissions measurements must be performed at least
from 30 MHz to 1000 MHz to adequately demonstrate compliance with Part 15
(15.109). Its guidance, the OET continued, applies to RF LED lighting
devices that, in the past, have been considered to operate on frequencies
below 1.705 MHz. Previously, devices operating between 9 kHz and 1705 kHz
had to be tested only for radiated emissions up to 30 MHz, where no
specified radiated emissions limits exist, and were exempt from testing
from 30 MHz to 1000 MHz. The OET said it recognizes that routine radiated
emissions measurements are needed under Part 15, based on the highest
frequency generated or used in the device.

"[W]e have found that emissions from RF LED lighting devices are
non-periodic, broadband in nature, and are produced as a byproduct of the
internal driver circuitry within the RF LED lighting device,"

the OET "knowledge database" paper said. "These types of emissions have
adequate energy and potential to generate radiated emissions well above 30
MHz."

The ARRL Lab's Electromagnetic Compatibility Engineer Mike Gruber, W1MG,
said he was pleased to see the FCC's OET clarify the test measurement
requirements. He said ARRL is generally hearing more RFI complaints
stemming from RF LED bulbs.

"Not only are the emissions limits higher for Part 15 LED bulbs - as
opposed to Part 18 fluorescent and CFL bulbs, they seem to be winning out
in terms of consumer popularity," Gruber said. "Higher limits and more
bulbs probably make for more complaints." Gruber said the Lab has seen LED
lighting devices causing problems in the 2 meter band. "Since conducted
emissions limits do not apply above 30 MHz, radiated emissions limits can
be the first line of defense against RFI at these higher frequencies."

Gruber pointed out that noise generated by street and traffic lighting can
be widespread. In such instances, he suggested that Part 15b limits for
residential areas should apply. "These limits are lower than Part 15a
limits, which are intended only for commercial and industrial
environments," he explained. "This is especially critical in cases where a
pole transformer connected to the lighting device also feeds a home or
residence. The 240 V split-phase secondary system can conduct RF into a
residence through the service entrance panel." He suggested that the lower
limits may benefit mobile users.

The OET noted that the ANSI Accredited Standards Committee C63-EMC is
drafting measurement procedures for lighting devices. "When complete, we
expect it will address in greater detail the measurement procedures and
configurations to be used in determining compliance," the OET said.

Fonte: ARRL
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