Triplett Mitigator Loop Coil – 3232 - Manual (Page 18)

12 Pulse: 660Hz, 780Hz, 1380Hz, 1500Hz, 2100Hz, 2220Hz, 2820Hz
[550Hz, 650Hz, 1150Hz, 1250Hz, 1750Hz, 1850Hz, 2350Hz]
11.1.6: “Off Frequency” Harmonics: Electronic Convertors
Various types of electronic power conversion devices are becoming more common. These devices
often convert the 60Hz [50Hz] power line current into some other frequency, often for the purpose of
controlling motor speed. Sometimes, heating equipment or lighting electronics is involved. Since the
converted frequencies are not multiples of 60Hz [50Hz], they stand out as “converted” frequencies.
11.1.7: “Off Frequency” Harmonics: Motors and Generators
Motors and generators can create off frequency harmonics that are close to 60Hz [50Hz] but off by
several Hertz (high or low). Facilities that have their own power plant can produce off frequency cur-
rents from their generators. These plants often incorporate diesel engines whose speed (RPM) is not
controlled precisely enough to produce exactly 60Hz [50Hz]. Induction motors run slower than “syn-
chronous speed” motors. This is due to an inherent “slip” effect between the rotor and the magnetic
field of the stator. The result can be “slot” harmonics that are off frequency by the amount of slip in the
motor.
SECTION 12: COORDINATION
Obviously, there is little that a telephone craftsperson can do to solve these power problems himself. If
it is known that the telephone wire plant is bonded, grounded, and balanced, as well as can be ex-
pected, then the only solution may be coordination.
Coordination simply refers to the power company and the telephone company working together in a
COORDINATED effort to solve the problem.
Why should the power company want to help? Often times they are REQUIRED to help solve telephone
noise problems that result from harmonic currents in the power line. Some states have enacted regula-
tions that set the maximum limits on radiated harmonic noise. Local Public Utilities Commissions usu-
ally stipulate that the different utilities work together to solve problems.
In addition, it is to the advantage of the power company to solve harmonic current problems. In severe
cases, the harmonic currents can damage power company equipment. Harmonic currents often cause
equipment, including the power lines themselves, to run hotter than usual. A 10 degree C temperature
increase (above normal operating temperatures) can cut motor life in half! Harmonic currents can also
cause metering errors, which affect the power company’s revenues. In general, harmonic currents have
no beneficial effects and are often detrimental to efficient operation of the power line.
From the power customer’s point of view, harmonic currents can cause excessive heating or failure of
various loads connected to the power line. If the power company is generating large harmonic currents
that end up being dissipated as excess heat in customer loads, that customer could legitimately litigate
against the power company for damage caused to their (the customer’s) equipment.
Obviously, the power company would want to curtail such occurrences by keeping their harmonics at
acceptably low levels. To this end, most power companies and telephone companies have worked out
informal or official channels whereby they can communicate and work together to solve their “joint”
problems.
If this is a power company problem, why does the telephone craftsperson have to identify the problem
and explain it to the power company? For several reasons. First, the power company is often unaware
of the problem. Noise Mitigators have joked for years about how they (the Noise Mitigators) act as
watchdogs for the power company’s harmonic problems. Telephone lines are great “detectors” of
harmonic problems in power lines. Second, the power company sometimes does not have any equip-
ment to measure the extent of the problem. The MITIGATOR and a Loop Coil, in the hands of a tele-
phone craftsperson, may be the only way that the power company can “see” the problem. This isn’t to
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