The origins of 60Hz as a Power Frequency
(Sorry for the poor copy and paste Some numbers and letters may have changed or lost altogether )
" Time is flying, never to return.
-Virgil
In 1891, Westinghouse engineers in Pittsburgh selected 60 Hz as their new power frequency. That same year, AEG engineers in Berlin selected 50 Hz as their new power frequency. Although much has happened since 1891, these two frequencies remain the principal power frequencies in use worldwide. Many people continue to be affected by the decisions on frequency standards made so very long ago. Travelers from Europe to North America often bring personal appliances with them that require
an adapter to allow operation of the appliance on the “foreign” power available here. Sometimes, engineers reapply electrical equipment designed for operation on one frequency to a power system operating at a different frequency. As a result of these and similar common situations, questions arise about why there are two frequencies. Is it really necessary to have two frequencies?
Why can’t everyone just change
and use one frequency? Which is the
“best” frequency? Questions about
power frequency continue to arise periodically,
and have done so for many
years. Answers to these questions are not
always as expected.
People sometimes wonder about the
geographical pattern of distribution for
the two standard frequencies. In particular,
why is one frequency used almost exclusively
in some regions of the world
while the other predominates in the remaining
areas? This line bf inquiry
sometimes leads those persons to suspect
a conspiracy on the part of manufacturers
to control markets or otherwise manipulate
the world for their own benefit.
People seem to love conspiracy theories.
Other people speculate that there
must be some pattern at work, the pattern
tern
based on the number 60. They observe
that there are 60 seconds in a
minute of time and 60 minutes to the
hour. Or angular units include 60 minutes
of arc to the degree and 60 seconds
to the minute, so what about 60 Hz? After
all, it seems only logical that 60 Hz is
somehow an extension of the same rationale
that produced these other units
of measure. In particular the units of
time, 60 cycles per second, 60 seconds
per minute, 60 minutes per hour seem to
be such a consistent pattern, more than
could be explained by mere coincidence.
However, the human mind is very good
at finding patterns, even when a pattern
does not exist.
The Story of the Frequencies
The story ofthe frequencies was told long
ago. Charles Scott and Benjamin Lamme
of Westinghouse both provided documentary
accounts early in the 20th century
[1, 2, 31. Lamme previewed his
information in a discussion of an earlier
paper by David Rushmore [4f.T hese
authors restricted their attention to
North American developments. Some
narrative accounts also survive even today.
These narratives are in the form of
legend and story. Once upon a time, informal
discussion between old-timers
and new engineers was a common way for
those entering the profession to learn
about the lore and practice of engineering
work. However, like the leaves ofautumn
in the springtime, those old stories are
mostly gone and forgotten. Now any person
wishing to explore the circumstances
surrounding adoption of either 50 or 60
Hz must rely on documents as primary
sources of information.
Prof. Harold W. Bibber (deceased) of
Union College once offered some brief
public remarks on the subject. The occasion
was the 43rd Steinmetz Memorial
Lecture in 1972. 1 Steinmetz was associated
associated
with GE; therefore he was a competitor
of those at Westinghouse making
decisions on 50 and 60 Hz.
Although a competitor, his personal
qualities, including insight and leadership,
brought him respect. During the
lecture, while Bibber recounted Steinmecz’s
contributions to technical standards,
he briefly repeated the story of
the frequencies. By his account, “the
choice was between 50- and 60-Hz, and
both were equally suited to the needs.
When all factors were considered, there
was no compelling reason to select either
frequency. Finally, the decision
was made to standardize on 60-Hz as it
was felt to be less likely to produce annoying
light flicker.”
Lamme’s latter account {If does not
mention light flicker as being the deciding
factor in the selection of 6O-Hz, and
therefore the reader is left to wonder
about both his earlier discussion {4] and
Bibber’s version. Since neither party is
now living, it is not possible to ask them
to clarify their statements. When assessing
the merits of various conflicting
claims, historians usually place greater
weight on contemporary wrirten accounts
made by principals. On this basis
Lamme’s account seems to be the more
credible.
(1, Nearly every year since 1925, the Steinmetz Memorial
Lecture Fund has provided for public lectures
by eminent scientists and engineers in honor
of Charles Proteus Steinmetz. The Schenectady
Section of the IEEE and Union College are cosponsors
ofthese lectures. The 43rd Steinmete Memorial
Lecture in 1972 was devoted to “Recollections
of Charles P. Steinmetz,” rather than being
about the science and engineering he represented.
That year, speakers were selected from among
those persons who had been personally acquainted
with Steinmetz. Prof. Bibber, a protege of Steinmetz,
was one of three lecturers to offer their personal
recollections of him.)
However, Prof. Bibber’s explanation
is the more correct, although
there have been times when even I was
skeptical. Two pieces of evidence support
the light flicker explanation, both
attributed to L.B. Stillwell, a principal
at Westinghouse. The first item is a
brief article published in the IEE Journal
before the turn of the 19th century. The
second is a letter from the archives of the
Westinghouse History Center in Pittsburgh.
Both are firsthand accounts from
Stillwell, one of the principals, stating
that light flicker was the determining
issue [5] [6].
Stillwell’s Account
In November 1890, Stillwell and
Byllesby returned from Europe. Stillwell
was promptly given the job of investigating
and recommending a lower
frequency than the 133 Hz frequency
that was their current standard. A few
months later, an informal committee
comprising Schmid, Scott, Shallenberger
(by one account, it was Lamme
rather than Shallenberger who was on
the committee), and Stillwell recommended
to Westinghouse management
adoption of two frequencies, namely, 60
cycles (Hz) and 30 cycles per second.
Stillwell recalled distinctly the final
meeting of the committee at which this
recommendation was agreed upon. They
were disposed to adopt 50 cycles, but
American arc light carbons then available
commercially did not give good results
at that frequency and this was an
important feature which led them to go
higher. In response to a question from
Stillwell as to the best frequencies for
motors, Scott said, in effect, “Anything
between 6,000 alternations (50 Hz) and
8,000 alternations per minute (67 Hz).”
Stillwell then suggested 60 cycles per
second, and this was agreed to. Shortly
afterward, the management of the company
informally approved the recommendations
of the committee and 60
cycles and 30 cycles became recognized
standards for new work [ S , 61.
Ironically, the first installation to use
the new 60 Hz standard was the Pomona
California plant described by Bill Myers
171. The irony comes from the role played
by A.W. Decker, first at Pomona, where
the new 60 Hz Westinghouse frequency
standard was introduced, and then a year
later at Mill Creek, where GE’s new
three-phase system and 50-H~st andard
frequency were both introduced [SI.
Decker was in the right place at the right
time to participate in making major
changes to the state of the art in electrotechnology.
Unfortunately, because of
poor health, he did not survive long
enough for his historic role to be properly
recorded. It wasn’t until 1915 that the
electrical pioneers began to document
their deeds in an organized manner.
If the question is “What is the best
frequency?”, the answer depends upon
when the question is answered and what
application is involved. The story is not
simple because it has evolved over at
least 130 years. In that time period, fundamental
changes in the application of
AC have led to radical changes in the
frequencies used [l}. The total period
needs to be considered by dividing into
different eras of electrical development.
Experimental Period (1 82 1 to 1880)
Electrotechnology has been developing
since 1821, when Faraday showed that a
compass needle is deflected by current
flowing in an adjacent electric conductor.
The years between 1820 and 1875 were
an experimental period in which inventors
conducted public experiments of interesting
phenomena. Although AC was
used during this period, its frequency was
barely recognized.
In 1831, Faraday demonstrated the
principle of electromagnetic induction,
where current flow in one conductor
can induce current flow in an adjacent
conductor by electromagnetic forces.
This phenomenon leads directly to the
use of AC, since magnetic flux linkages
must constantly change in the coupled
circuit to produce any sustained electrical
effect.
In 1832, H. Pixii developed the
split-tube commutator for generator operation.
His commutator opened up the
field to DC applications, which then
came to the forefront offurther electrical
developments. Some people say Pixii’s
commutator set electrotechnology hack
SO years by allowing DC to take an early
lead and postponing development ofAC
until Tesla and Ferraris revealed the concept
of polyphase current. This claim is
not true because AC did continue developing
during the period between 1830
and 1885. However, further development
was severely retarded because electrical
theories of that time were often
based on hydraulic analogy. IC was difficult
to imagine any useful work being
done by “causing water to slosh back and
forth in the pipe.” There were other naive
opinions of that era that are equally humorous
by modern standards. AC was regarded
with distrust until engineers, like
Steinmetz, Kennelly, Lamme and others,
provided the conceptual underpinnings
allowing practical applications.
However, there were a few problems
along the way. DC did not flow
smoothly to all future applications, and
AC was used to circumvent problems
with DC. The Alliance machine was the
first to provide AC power for commercial
applications. In 1849, Nollet, professor
ofphysics in the Military School of
Brussels, took earlier machines by Pixii
and Clark and increased the number of
coils to obtain a stronger current [9].
(Prof. Nollet is not Jean-Antoine
Nollet, a contemporary of Benjamin
Franklin [lo].) Finally, Prof. Nollet arranged
16 coils on the same disk turning
between the arms of eight magnets, and
placing several disks upon the same axis,
he created the Alliance machine (see
Fig. 1). Unfortunately, the commutator
sparked excessively, and it was necessary
to replace it with slip-rings to obtain
prolonged operation. Attention was
turned to the availability of electric
light for illumination of ships and lighthouses.
The first such application of AC
was in a lighthouse located at La Heve,
France, in 1863. Slip-rings were used,
and AC was produced because they did
not know how to avoid commutator
sparking and excessive wear. The Alliance
machines had 16 poles and turned
at 400 RPM, thereby producing AC
with a nominal frequency of 53 Hz. The
electrical potential was reported to
equal 226 Bunsen cells, equivalent to
430 volts, an average.
In this early period, these inventors
were severely impeded, not only by limited
understanding, but also by an absence
of standard nomenclature.
Frequency was not considered very important.
As a result, today when we read
their accounts, it is hard to follow their
discourse and understand their results.
They did not speak about hertz, as we do
today, or even C.P.S. (cycles per second),
as we did prior to 1968, when IEEE
changed the designation. They spoke
about alcernarions, full-alternations,
turns, and periodicity. Reference to
“Siemens type alternator operating at
1,000 turns and producing 16,000 alternations”
meant a 16-pole generator
operating at 1,000 RPM and producing
an electrical output of 8,000
cycles per minute (133 Hz).
The term alternation often
meant only a half-cycle, but
you can’t always be sure. This
reference was to the Siemens
type alternator used by William
Stanley in 1886 to demonstrate
a system of
alternating-current distribution
in Great Barrington,
Mass.
To be certain of the frequency
actually in use, it is
necessary to determine by calculation,
using number of
magnetic poles and operating
speed. The Alliance machine at
La Heve had 16 bobbins (poles)
on each rotor disc and operated
at 400 turns (see Fig. 2). When
this information is used in
Equation (1), the answer is
53-H~
Frequency= [Poles/2 x RPM/60]
There were other applications
of AC power for lighting. One of
those was Jablochkoff Candles, used in
Paris for illumination in 1876. To obtain
equal rate of electrode consumption,
they used AC power from a
Grammes AC generator
light Period (1880 to 1890)
The Light Period is normally considered
to have begun in 1882 with Edison’s
Pearl Street station. In 1884, Dr.
Hopkinson demonstrated AC electric
power transmission over short distances
and Gibbs & Goulard exhibited
their transformers at the Turin Exposition.
Meanwhile, Zipernowski, Deri,
and Blathy at Ganz and Company were
also developing their own transformers,
In 1886, Galileo Ferraris was conducting
public experiments with
polyphase and William Stanley demonstrated
his system of single-phase
AC distribution for lighting, an extension
of the previous work by both
Gibbs & Goulard and Zipernowski et.
aL at Gam and Company.
In his demonstration system at Great
Barrington, Stanley used a Siemens type
alternator obtained by Westinghouse
from Gibbs & Goulard in England. The
alternator had 16 poles and was operated
nominally at 1,000 RPM,
hence 113 Hz. This was the
beginning of t h e h i g h -
frequency era in North America.
Westinghouse followed
the lead established by Stanley
in Great Barrington and
continued use of 133 Hz as a
standard frequency. Meanwhile,
T-H (Thomson-
Houston) in Lynn, Mass.,
gravitated toward use of 125
Hz and Fort Wayne Jenny
Electric used 140 Hz as their
respective standard frequencies.
There was no single high
frequency used by everyone,
but Lamme used the expression
“approximately 130 Hz”
to identify the group fl).
Mranwhile, in Europe the
trend was to use much lower
frequencies. In 1889, Ganz
and Company used 42 Hz,
and Dobrowolsky at AEG
used 30 Hz. AEG & Oerlikon
used 40 Hz for their Frankfort-Lauffen transmission
system in 1890. In 1891, AEG raised
their standard frequency to 50 Hz. This
was done to avoid any possibility of light
flicker, as learned from the 40 Hz frequency
used in the Frankfort-Laden system.
That is where our story began.
Power and Light Period
In 1890, engineers at Westinghouse recognized
that use of high frequency was
impeding development of their induction
motor. This was the primary reason
for their change to 60-Hz.
At GE, it was 1893 before they realized
the need for a lower frequency.
Henry G. Reist and W.J. Foster continued
the work began by Danielson in
1890. When Steinmetz came to T-H in
January 1893, work on the three-phase
system was well under way. A few weeks
after moving from Eichmeyer to T-H,
Steinmetz found himself at Hartford,
Conn. A problem with equipment sold
to Hartford Electric had everyone baffled.
Steinmetz was able to identify the
cause as a transmission line series resonance,
excited by harmonics of the 125-
Hz power used. His proposed solution
was to reduce the frequency of the system
to one-half its initial value. This
would have been 62.5 Hz, very close to
Westinghouse’s 6 0 - ~ zs tandard. On
further consideration, GE elected to use
50 Hz, the same as used by its European
affiliate AEG. Later in 1893, when Mill
Creek was commissioned in California,
it operated at 50 Hz, the new GE standard
frequency for power applications. A
year later, GE found itself lagging behind
Westinghouse in the sale of AC
equipment and changed once again, this
time to 60 Hz. Reist continued to advocate
50 Hz until the 1920s.
Period of Systems Interconnection
The Mill Creek installation placed much
of Southern California on a 50-Hz path
that remained unchanged until after
World War 11. It was not easy to change
over all that installed base of 50-Hz
equipment, to operate at the new ~O-HZ
frequency. Southern California Edison
began planning in 1925 to make the conversion.
It was not completed until 1948.
England also experienced great difficulty
in converting their local networks
to a uniform frequency of 50 Hz. This
was necessary to permit interconnection
of the local autonomous networks into
national grid. In the period 1924-1927,
the Weir Committee considered the issue
and selected 50 Hz as the new standard
frequency CO be used by the
also-new Central Electricity Board.
Work on the conversion was not completed
until 1938 at an expense of 17.3
million pounds I1 11.
Japan experienced a different result.
Their country was divided into two regions,
each with a different standard frequency.
IC began in 1889, when two
Japanese engineers departed Yokohama
for a tour of North America in search of
electrical technology. They were looking
for ideas to develop the Keage Canal project.
They returned home with the necessary
information and contacts to encourage
them to use electric power. Their generator was made by SKC Chesney) in Pittsfield,
Mass. SKC was formed by William Stanley after he left Westinghouse in 1889. Their
frequency was 133 Hz, the standard frequency advocated by William Stanley long after everyone else realized it was too high for power applications. In 1895, AEG sold a 50-Hz generator to the power company in Tokyo and the astern half of Japan was pur on the
50-Hz path. A little over a year later, GE
sold a 60-Hz generator to the power company
in Osaka, and the Western half of Japan
was put on the 60-Hz path (see Fig. 3).
Conclusion
Engineers have always used the “best”
frequency for the purpose at hand,
whatever the circumstances. Major
changes in the particulars have occurred
several times in the 100 years
since 50 and 60 Hz were selected in
1891. The standard for power frequency
was settled only in modern
times. There were very many standard
frequencies in use, even as recently as
20 years ago. The outcome was determined
by operating conditions in the
field, not exploitation of particular systems
to limit competition. The efforts
of engineers were directed to overcoming
defects, not fighting each other.
Acknowledgment
This article is dedicated to E.A.E. “Ted”
Rich, whose patient encouragement has inspired
the research it represents. Any errors
or omissions lie strictly with the author."
