- Pulse Calculator
- Features
- Info Sheet
- How Does Pulse Work
Temperature compensation built in
Guy wire breaking strengths are referenced at 60°F. Calculations require input of ambient temperature, formulas adjust accordingly
Inspection Mode
Input of exisitng wire pulse time measurements using stop watch, output exisitng wire tensions
Plumb and Tension Mode
Input guy wire profile details ( size, elevation and anchor horizontal distance) , output calculates pulse times required to acheive proper tension. One limitation- simple triangulation used, no provisions built in for offset of anchor elevations
Adjustment for irregular design loads
Guy wire working loads @ 60°F are normally calculated at 10% of breaking strength. Occasionally engineers will design to a slightly different percentage of BS. Default on calculations is set at 10% however this can be changed
Wire Sizes From 3/16" to 1"
Drop down list of wire sizes for quick entry.
All data for wires 5/8” and under is for EHS and 11/16” and above is BS.
Inline with calcs by Structural Software
Comparisons have been made with real world manufacturer prints and structural software
Calculates 10% Upper/Lower Deviation
Acceptable norm for wire tensions is typically plus or minus 10% of the temperature compensated design load. These limits are calculated and output on form
Info sheet -Use the "I-Paper" Icon to print
The following is an exerpt from:
EIA/TIA 222-F
ANNEX E: TOWER MAINTENANCE AND INSPECTION PROCEDURES
(parts I. to III. have been omitted)
IV. Methods For Measuring Guy Initial Tensions
There are two basic methods of measuring guy initial tensions in the field: the direct method
and the indirect method.
A. The Direct Method (omited from this doc)
B. The Indirect Method (see Figures E8 and E9)
There are two common techniques for the indirect measurement of guy initial tensions: the pulse or swing method (vibration) (Figure E8) and the tangent intercept or sag method (geometry) (Figure E9).
1. The Pulse Method (see Figures E8 and E10)
One sharp jerk is applied to the guy cable near its connection to the anchor causing a pulse or wave to travel up and down the cable. On the first return of the pulse to the lower end of the guy cable the stop watch is started. A number of returns of the pulse to the anchor are then timed, and the guy tension is calculated from the following equations:
in which (see Figure E10)
TA = Guy tension at anchor (lb) .....
TM = Guy tension at mid-guy (lb)
W = Total weight of guy, including insulators, etc. (lb)
L = Guy chord length (ft)
V = Vertical distance from guy attachment on tower to guy attachment at anchor (ft)
H = Horizontal distance from guy attachment on tower to guy attachment at anchor
fit)
N = Number of pulses or swings counted in P seconds
P - Period of time measured for N pulses or swings (s)
Instead of creating a pulse that travels up and down the guy, one may achieve the
same result by causing the guy cable to swing freely from side to side while timing N
complete swings. The formulas given above will also apply for this approach.
Click for Info on Tangent Intercept Method (below)
2. The Tangent Intercept Method (see Figure E9)
A line of sight is established which is tangential to the guy cable near the anchor end
and which intersects the tower leg a distance (tangent intercept) below the guy
attachment point on the mast. This tangent intercept distance is either measured or
estimated and the tension is calculated from the following equation:
in which
C = Distance from guy attachment on tower to the center of gravity of the weight W (ft)
I = The tangent intercept (ft)
ff the weight is uniformly distributed along the guy cable, C will be approximately equal to 1-I/2. If the weight is not uniformly disWibuted, the guy may be subdivided into n segments and the following equation may be used:
in which
Wi = Weight of segment i (lb)
Ci = Distance from the guy attachment on the tower to the center of gravity of segment i (ft)
If the intercept is difficult to establish, one may use the guy slope at the anchor end with the following equation:
in which
cz = Guy angle at the anchor (see Figure E9)
Note that
and that
and that WC in equation (7) may be replaced with S, as was done in equation (5).
