Absorbing Clamps to measure EMI Emissions according to CISPR 14 or EN 55014
absorbing clamps also known as ferrite clamps are used for measuring
radio noise power in lieu of radiated emissions measurements.
These absorbing clamps meets CISPR publication 14 (EN 55014)
for the measurement of interference from household appliances,
electrical tools and similar apparatus. It measures radio noise
power generated and fed through the power cables of these products
above 30 MHz.
absorbing clamp consists of a calibrated ferrite current transformer
operating in the frequency range of 30-1000 MHz and two groups
of ferrite rings. The ferrite rings acts as an absorbers of
energy and stabilizes impedance. One set of ferrite rings surrounds
the lead from the transformer to the EMI meter to minimize standing
waves. The second group of ferrite rings surround supply cable
from the equipment under test. These rings act as an absorber
of energy and an impedance stabilizer to isolate the equipment
under test (EUT) from the external power source. These rings
are made up of two halves. Therefore, the power cable from the
EUT can be placed inside the aperture of the rings.
Com-Power absorbing clamps are individually calibrated before
shipment with equipment traceable to National Institute of Standards
and Technology (NIST). The data and the certificate of calibration
are shipped with each unit.