Rewind and definition by direct method - ideal measuring method of cable length. But this option, demanding availability of the special machine and operating crew, is not suitable for use in usual conditions.
It is required to you
- - cable of certain length;
- - steel tape measure;
- - table of key parameters of cables;
- - rope;
- - wedge clip;
- - caliper;
- - calculator;
- - TT-50 theodolite;
- - safety harness;
- - assembly claws;
- - coupling armature;
- - combination pliers
Instruction
1. Find cable length when mounting power line. Define distance between support and also between subjects to transfer and the extreme columns, next to them, at the beginning and at the end of the line. Summarize the received values, having added to them length of increments of cable on support and the connected objects.
2. Determine length of cable which has remained on drum after its partial use or in case of lack of marking with the indication of length on full hank. Consider that similar measurement has certain error. If it is possible, measure length and diameter of neck of drum. Otherwise use the special table and find the corresponding parameters by number of drum.
3. Determine diameters of cable and the reeled-up wire. Designate length of wire and neck of the Ln and Lsh reel, and diameters of the reeled-up wire, necks of drum and cable according to Dv, Dsh, Dk. Find required cable length, having substituted the received values in formula: Lp = 3.14*lsh * (2dv – 2dsh) / 4*2Dk.
4. Use the geodetic device and measure necessary cable length. Make distance projection between fastenings for wire on columns or other support by means of theodolite (TT-50). Measure the received distance between projections steel tape measure. To the received value add length of dip and increment for mounting.
5. In the absence of geodetic tools use alternative method of measurement of cable length. Consider that this option demands strict observance of safety measures and big time expenditure. By means of safety harness and assembly claws fix by coupling armature the free end of cable for the insulator.
6. Using rope and wedge clip, pull wire between support, adjust has sagged and impose bandage. Lower cable on the earth and measure from bandage length of fittings with insulators.