Page 141 - Pipeline Rules of Thumb Handbook

128 Pipeline Rules of Thumb Handbook

X = 100 + 10 Example. How far is the line-of-sight distance to the
horizon in an airplane flying at an altitude of 4,900ft?
+
3
,
X = 10 ++ or 13miles ( 4 900 = 70)
X = 4 900 + 70
,
Distance between towers can be 2X or 26 miles.
+
This same formula can be used to estimate distances in =X 70 8
an airplane. Distance to horizon is 78 miles.
For quick determination of the horsepower per ampere for induction motors (3 phase)
at different voltages

Voltage hp per ampere

480 1
2,400 5
4,160 8

Chart gives electric motor horsepower for pumping units

This chart provides a means of determining the power
requirements for a beam pumping installation powered by an
electric motor based on a fluid with a specific gravity of one,
with fluid at the pump. The power requirement determined
by the chart includes a mechanical efficiency factor of 0.45
and a cyclic factor of 0.75, which factors are frequently
applied to motors used in sucker rod pumping service.
An arrangement is available for correcting the power
requirement in the case of an underloaded pumping unit. The
example shown in the chart is self-explanatory.
After the power requirements are determined from the
chart the next higher size of commercially available motor
is used.