Classic Mode

Music Trade Review

Issue: 1916 Vol. 62 N. 9

Music Trade Review -- © mbsi.org, arcade-museum.com -- digitized with support from namm.org
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THE MUSIC TRADE REVIEW
Some Interesting Facts and Figures Regarding Power Usage and Wastage
in Player-Pianos-The Results of Exhaustive and Accurate Tests Presented
in Chart Form—The Many Varied Factors in the Consumption of Power.
pneumatics is extremely small in proportion.
We need not point out, of course, that to have
anything like accurate data in matters of this sort
is of the highest importance, because only thereby
can one be enabled to quit the valley of indecision
and the fog of guesswork for the higher levels of
science. The more we know of such matters as
these the more guides we have in trying to find
the way to the perfect design. Hence the im-
portance of accurate experiment and sound pre-
liminary scientific training.
The assertions which have been made in this
department regarding the distribution of the power
From time to time in the Pneumatic Depart-
ment of the Player Section we have directed at-
tention to important questions relating to con-
sumption of power in the player mechanism. We
have pointed out that exact knowledge on this
topic is scarce and that there is much confusion
in the minds of technical men, not to mention
dealers and salesmen, in connection with the en-
tire matter. In some recent articles we have in-
sisted on the assertion that the proportion of the
total power input (whether this arises from the
direct operation of foot-driven bellows units or
from some form of power-driven vacuum ap-
ALOCIAN CO 1 *. ROLL aoi3o.
WATTAGE: CURVES OF
— Music ROLLS.-
Longitudinal spaed one » one half" inches per
Cach verlical spacs 125 waifs.
T ? d from k/} lo ngbh
inu Co'3. graphic waKnwtcr-,
,
Kccerd made Jan. 17- 1916
». 72 No. 3.
Ov««TV«
ax * t .
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paratus) absorbed in the operation of the roll
driving motor is unreasonably large, amounting
to not less than 50 per cent, in many, if not in
most, cases. We have also pointed out the high
probability that experimental analysis would show
the greater part of the remaining power input to
be absorbed in the operations incident to main-
taining a partial vacuum in the chests and that
the actual condensation in these chests produced
by the direct flow of air into them from collapsing
1
1
\.——
I
input were based upon purely mathematical rea-
soning and lacked experimental verification.
Owing, however, to the kindly interest of a friend
whose eminence in the world of engineering is
generally acknowledged by his contemporaries, but
who prefers not to have his name mentioned, as
he has no other than a scientific interest in the
matters at issue, we have been enabled to obtain
some extremely interesting graphic records re-
lating to the general subject of power consump-
tion and its important subdivisions, distribution of
input, proportion of total power absorbed by
motor, etc. Thus the technical readers of The
Review may obtain some definite facts upon which
to base further experimentation with a view to
further improvement.
A few words of explanation are necessary con-
cerning the chart records herewith shown.
These curves are graphic records taken on a
recording wattmeter and show the fluctuations
in wattage for an electric motor used in driving
the vacuum system of a player-piano. The rec-
ords were made, as will be understood, while the
player-piano was being used in the performance
of the various pieces whose names are appended.
They do not show directly the rise and fall of
vacuum level, but rather the rise and fall of
electric power consumed in generating the various
vacuum levels required and attained during the
performances of the pieces mentioned. Hence
the indications are indirect, although at the same
time accurate, for it is plain that the electric
power consumption varies directly as the load on
the vacuum system. While, therefore, a given
peak in a curve might merely mean that many
pneumatics are speaking on a low level of tension,
this is in effect the same thing to us as the speak-
ing of fewer pneumatics on a higher level, since
for our purposes the important fact is as to the
displacement capacity of our player primarily. It
must be understood that the player-piano from
which these records were made is operated by a
somewhat unusual and entirely original type of
vacuum system whereby a constant level of forty-
four inches water column is maintained, the lower
speaking level being reached through expression
governors. The wattage curves are therefore di-
rectly indicative of the fluctuations in displace-
ment quantities; that is to say, in the amount of
air being displaced from moment to moment.
Operating with a Blower.
The player-piano is power driven by a \ x k-
horse-power electric motor operating a six-stage
centrifugal vacuum blower in place of the ordi-
nary exhaust bellows. A vacuum of forty-four
inches water column is maintained at the player
constantly. The fact that the exhauster works
constantly and not reciprocally has the effect, of
course, of flattening somewhat the curves, since
there is a certain amount of stored energy in the
motor, as it were, due to the flywheel effect of
steadily rotating parts. With a reciprocating bel-
lcws system, such as is generally used, the curves
would have sharper slopes and peaks.
To anticipate objections from the start let it be
said that the player operates on 7 inches water
column when governed down to the minimum and
that changes from this level up to forty-four
inches can be had instantaneously. Forty-four
inches water column correspond to about \Vz
pounds effective pressure per square inch. It is
admitted that this high vacuum maintenance is
expensive relatively speaking, as the motor uses
1,125 watts, but the dynamic effects possible with
such a power reserve justify any expense in-
volved. Moreover, the curves are not in the least
invalidated as authorities in our discussion, for
they are substantially accurate in proportion to
any power level postulated. A system of opera-
tion based on a normal maximum and throttling
down to the speaking power required from
moment to moment, has, of course, the immense
advantage that all non-speaking pneumatics oper-
ate instantly, without any chance of their refusing
to work through lack of power. Also it means
(Continued on page 8.)
Music Trade Review -- © mbsi.org, arcade-museum.com -- digitized with support from namm.org
THE MUSIC TRADE
8
REVIEW
POWER CONSUMPTION—(Continued from page 7).
much higher possible motor speed when required,
extremely rapid re-roll speed and other advan-
tages too numerous to mention, among which,
however, must be included the relatively enor-
mous advantage of having instant speech at the
maximum from any lower level.
Apart from these considerations, however,
which are more or less academic from the view-
point of the present article, the curves are ac-
curate and immensely valuable for all of us.
The recording instrument used in the tests is
the Esterline Co.'s graphic wattmeter. The paper
strip on which each curve is drawn consists, as
will be seen, of four horizontal parallel lines,
with vertical lines at regular intervals cutting the
horizontals. Each of the equal spaces enclosed
by the verticals represents a time interval of one
minute and the strip travels in one minute the
length of one of these, which is actually 1M>
inches. The illustrations given herewith are, of
course, considerably reduced. Thus, as will be
seen, most of the curves represent about ten min-
utes of playing.
Each of the spaces between two of the hori-
zontal lines represents 125 watts and, as will be
observed by examining the beginnings of the
curves, the motor uses about 1,188 watts to main-
tain the speed of the blower for forty-four inches
water column vacuum before the roll begins to
move or the pneumatics to speak. The curves
show, in fact, that to maintain a vacuum in the
chests and channels of a player, without any play-
ing going on, in itself absorbs more than half the
available power.
gradual increase in load due to the increasing
weight of the take-up spool as the roll winds up.
Similar comparisons may be made in the case
of curves N and P. It ought to be mentioned that
a still better method of comparison would be to
photograph two of these companion curves on
two glass plates such as are used in making lan-
tern slides, and then fasten one exactly over the
other so that both at once can be shown by a
projecting lantern. This immensely enlarges the
curves, making them easy to follow and furnish-
ing a remarkably valuable comparison of power
consumption fluctuations.
Incidentally it may be noted that the re-roll
peaks are very high and their duration time very
short. This is due to the fact that the motor in
the player-piano, which has furnished the means
for these experiments, is set to run at the very
high speed, when re-rolled, of 450 feet per minute.
The facts thus revealed, namely, the dispropor-
tionate drag of the roll-driving motor and the
consumption of power in maintaining a vacuum
in the chests and channels, show concretely some
defects in player design of which the existence
has long been suspected. It is well that unim-
peachable evidence should be produced to show
how much remains to be done before we can say
that anything approaching an ultimate design has
been accomplished.
We shall be happy to give further information
on these matters to any inquirer who will address
the Plaver Section editor.
PLAYOTONE AND BEHR BROS. SALES.
Hext Music Co. of Denver Doing a Very Active
Business.
H. E. Watson, representing the Mutual Oil Co.,
ol Kansas City, in the Wray, Col., district, recently
purchased a Hardman, Peck & Co. Playotone from
the Hext Music Co., of Denver. The same firm
also sold two Behr Bros, pianos last week, one to
Miss Fay Vandeveer, of the Harvard Hotel, and
the other to Mrs. H. Hutchinson, a Denver mu-
SOLVED-
The Tracking Problem!
A SECOND ANNOUNCEMENT OF A GREAT DISCOVERY!
What the Curves Represent.
Attention is now directed to the curves. The
double curve "I" may be studied to advantage.
Here is shown, on the right, the wattage for play-
ing Schubert's "Who Is Sylvia?" and on the left
the consumption when running the roll over the
tracker bar silently at tempo 70. The average
tempo of the piece is less than seventy, and so
the right hand curve, which, of course, varies as
the time occupied, is longer than the left hand
one. It will at once be seen (1) that the mainte-
nance of a vacuum is the great task, (2) that the
motor drag alone is responsible for more than
one-half of the power consumption, (3) and that
the speaking of the pneumatics does not produce
anywhere very sharp peaks and therefore no-
where any very great increases proportionately in
power consumed; that is, in air displaced. The
piece is a song arrangement, has an elaborate ac-
companiment with a singing melody cut in fairly
long perforations and maintains about the same
level of dynamic intensity from end to end, the
average tone strength being mezzo-piano or piano.
The facts thus disclosed are still more remark-
ably set forth in comparison of the curves "J" and
"K." The second of these shows the power con-
sumption in playing Liszt's second rhapsody,
where sudden changes of dynamic level are many
and where the general strain on the vacuum sys-
tem is great from end to end. Compare this
curve (K) with the one above it ( J ) , which
shows the power consumption in running the same
roll over the tracker bar silently at tempo 70. A
still better comparison can be had as follows : Cut
out these two curves from the illustration, mount
each separately on cardboard and hang them both
on pins, so that they are exactly in line with each
other, in front of a camera. If now they are
hung up on two parallel pins going through the
top corners of each card, and with the two cards
exactly on a level, a photo may be taken of the
first card, and when the shutter is closed the first
may be removed and the second photographed on
the same film. Then there will appear a com-
posite photo showing the one curve superimposed
on the other. This will show clearly what can be
seen less accurately by visual comparison of the
two curves side by side; namely, that the motor
is the greatest power waster in the whole player
mechanism. It is easy to see at once that the
motor-alone-curve maintains nearly as high an
average level as does the other. Fluctuations in
the motor-alone-curve correspond to fluctuations
in motor speed, of course, together with the
Such an assertion has been made more than once in various
quarters; so we shall not object if our statement is accepted with
reserve. Yet it is true.
Schulz Dealers are now being made acquainted with a new, efficient,
simple method for abolishing forever all tracking troubles, irre-
spective of the condition of the music roll.
The means whereby this method has been made possible consist of
what is called the
M. Schulz Company
Roll Centering Device
(Patented)
The depression of one lever at the moment the roll is ready to start
over the tracker-bar serves, in this wonderful system, permanently
to center the music roll between the chucks and on the tracker-bar,
in such a way that no difficulty in registration can occur when once
this has been done.
No Pneumatics
Absolute Certainty
No Perforations or Flanges
Absolute Simplicity
No Complication
Absolute Rightness
Schulz Dealers Have the Biggest Talking Point
in the Player Business Today. Get in Touch
With this Wonderful Development
Get full particulars from us: Send for Free Booklet entitled, "Correct
Tracking of the Music Roll—a Problem and How it Was Solved."
M. SCHULZ COMPANY
GENERAL OFFICES
711 Milwaukee Ave., Chicago
CHICAGO
SOUTHERN WHOLESALE BRANCH
730 Candler Bldg., Atlanta, Ga.

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