Hour meters may have a counter dial, as shown in
figure 6-80, view A, or a radial dial, as shown in views
START
0100
B and C. The use of different dial configurations on
COUNTER
hour meters causes a great deal of confusion for many
of the personnel who are responsible for reading the
meters. (Compare the three dial configurations shown
in figure 6-80.) The meters are easy to read, but each
must be observed very closely and considered
individually. The second number from the right on the
ASf06081
meter in view A is in tenths; therefore, the meter
Figure 6-81.--Start counter meter.
indicates 143.75 hours. On many meters with this type
items of equipment as gas turbine compressors on
of dial, the first number on the right is in tenths
which the number of starts is of vital importance.
(indicated on the dial of the meter); and if this were the
case, this particular meter would be indicating 1,437.5
The start counter in figure 6-81 is shown mounted
hours.
in the electrical control box of a GTC 85-73. It is also
used on other items of support equipment. This start
The fractional numbers (tenths and hundredths) are
counter is provided with a plate incorporating four
usually a different color. When the primary numbers
windows with dials showing through. The first dial on
are black, the fractional numbers are red.
the right records starts in increments of even numbers,
At a quick glance, the hour meters shown in views
zero through eight, and any odd number between is
B and C look the same, but from a closer examination,
indicated when the numbers stop at any intermediate
you can see that identical hands traveling the same
point between any two even numbers. The second dial
distance indicate different amounts of time. For
from the right records starts in tens, the third dial from
example, on the meter shown in view B, when the large
the right records starts in hundreds, and the fourth dial
hand (outer scale) has traveled from "zero to one," l
from the right records starts in thousands. The dials that
hour has passed, but on the meter in view C, 10 hours
record starts in tens, hundreds, and thousands show
would have passed. Therefore, determine how each dial
both odd and even numbers.
is calibrated before taking a reading. Always read the
scales in descending order. For example, on the meters
Speedometer and Tachometer
shown in views B and C, read the inner scale first,
middle scale second, and the outer scale last. On the
A speedometer (fig. 6-82, view A) is used to
meter shown in view B, the inner scale indicates 100
indicate vehicle speed in miles per hour. An odometer
hours, the middle scale 30 hours, the outer scale 6
hours, and, putting them all together, the meter
indicates 136 hours. The meter in view C indicates
30
20
2,570 hours.
40
10
The purpose of the small hand located below the 9
50
0
on the meters shown in views B and C is to indicate
60
whether or not the meter is operating. Movement of the
MI
R
large hands cannot be detected by looking at the meter,
LE
S PER HOU
but movement of the small hand can be detected easily
(A)
with the eye.
Start Counter Meter
20RP 30
M
The start counter (fig. 6-81) is an electrically
10
operated additive meter, which is normally used to
40
record the total number of complete starts of an engine
0 50
(B)
since initial or overhaul installation. The start counter is
AC
only used on a few items of support equipment;
ASf06082
however, it does provide valuable information on such
Figure 6-82.--(A) Speedometer; (B) Tachometer.
6-67
