GMP Strand Tensionmeter Operation and Maintenance Manual 1
Table of contents General Precautions Calibration Chart Temperature Compensation Charts Dial Using the Tensionmeter Accessory Saddle Re-calibration General An intensive study by the National Electric Safety Code Clearances Subcommittee has resulted in a completely new "Uniform System of Clearances" adopted in the 1990 and subsequent editions of the NESC.
The following list shows the various sizes, types and designations of messenger cables for which the tools can be calibrated: Nominal Diameter Inches mm Designation 1/4 6.35 6.6M Description 1 X 7 EHS 5/16 7.94 6M 1 X 7 Utility Grade 5/16 7.94 10M 1 X 7 EHS 3/8 9.52 10M 1 X 7 Utility Grade 7/16 11.11 16M 1 X 7 EHS 7/16 11.
The Tensionmeter is primarily made from nickelplated steel and is furnished in a hard shell plastic carrying case; the interior is cushioned with foam for unit protection. Each Tensionmeter has a registered serial number stamped on the unit. pPrecautions • • • • • • • • • Do not measure tensions of 1/2" diameter strand with the cable in place; these tension values usually exceed 10,000 pounds. Do not drop or jar the Tensionmeter. Raise and lower the instrument with a hand line.
Calibration Chart Included with each Tensionmeter is a calibration chart registered under the same serial number as the Tensionmeter. This chart is to be used for interpreting the readings for that specific instrument only. No other chart should be used. No other type of strand should be used. The table across the top of the chart lists the commonly used strand sizes for which the Tensionmeter was calibrated, as well as the handle position for each type of strand.
Temperature Compensation Charts (continued) Line charts are provided in these instructions in order for the user to determine how to compensate for changes in ambient temperature. The charts are derived from the recommended values expressed in the referenced industry standard practices. They are not intended to supersede any tension calculations which might be provided to the user by the utility's plant engineering department.
1/4” Extra High Strength Temperature Compensation Chart Per BSP 627-210-018 iss.
1/4” Extra High Strength Temperature Compensation Chart Per GTEP 627-100-200 iss.
5/16” Extra High Strength Temperature Compensation Chart Per GTEP 627-100-200 iss.
7/16” Extra-High Strength Temperature Compensation Chart Per GTEP 627-100-200 iss.
5/16” Utilities Grade Temperature Compensation Chart Per BSP 627-210-018 iss.
3/8” Utilities Grade Temperature Compensation Chart Per BSP 627-210-018 iss.
7/16” Utilities Grade Temperature Compensation Chart Per BSP 627-210-018 iss.
1/2” Utilities Grade Temperature Compensation Chart Per BSP 627-210-018 iss.
Dial The calibrated dial reads 0 to 100. The majority of recorded measurements will be within this range and are readjust as the graduation appears on the dial. However, on high load measurements, it is possible for the needle to make one complete revolution past zero. For these readings, it is necessary to add 100 to the graduation indicated by the needle.
Using the Tensionmeter (continued) Locate the column on the calibration chart for the grade and diameter of strand to be tested and note the correct handle position. (An asterisk alongside of the handle position number means that the accessory saddle must be used.* See the next section titled Accessory Saddle before proceeding.) Pull the handle down until the bottom edge of the cam plunger moves upward and stops at the correct position numbered on the cam case.
Accessory Saddle Certain Strand Tensionmeters manufactured and sold between Jan. 1991 and July 1992 had cam plungers of a different design than either the AT&T units which preceded them or the current GMP design which follows them. These units bear serial numbers in the range 1700-2300 stamped on the handle. When checking the tension on 1/4”, 5/16” or 3/8” diameter strand, a part called the accessory saddle block must be used to achieve dial indicator movement and a correct tension reading.
Recalibration To maintain optimum service, the Tensionmeter should be re-calibrated periodically. With moderate to heavy use, a calibration check should be performed every year. The initial calibration date is shown on each calibration chart. No attempt should be made to disassemble, repair or recalibrate in the field. If a unit is not responding to normal use, it should be placed in the carrying case with the calibration chart and returned to General Machine Products Co., Inc. for service.
General Machine Products Co., Inc. 3111 Old Lincoln Highway Trevose, PA 19053-4996 USA TEL: 215-357-5500 FAX: 215-357-6216 E-MAIL: info@GMPtools.com WEB: http://www.GMPtools.com GMP reserves the right, without notice, to make changes in equipment design or components as progress in engineering or manufacturing methods may warrant.
