Cables three-core

Gland plate Three to four mm of MS or non-magnetic material, depending upon the number, sizes and type of cables (single core or multicore) it has to carry (Figure 13.33). 

Figure A16.2 Three-core XLPE cable (Courtesy CCI)...

Table A16.5 HT Cables up to 11 kV Armoured three-core power cables 1.9/3.3 kV ...

Table A16.6 Armoured three-core power cable 3.8/6.6 kV (grounded system)...

Martin Hochstadter introduces a three-core power cable that does not become deformed or burn by the high voltage electricity. 

Table 16.6 Comparison of parameters for 1900/3300 V XLPE insulated, armoured, three-core cable...

The insulation screen is important in three-core cables because it prevents the inter-core electric stressing that would occur if the screen were not present. It maintains a radial stress pattern in each core, which is independent of the other cores. 

A similar reduction in rated current occnrs when several conductors are combined in one cable. Single-core cables can carry more current than three or fonr core cables. Vertically run cables carry less cnrrent than those run horizontally by a factor of approximately 5%, dne to the convection of heat given ont by the lower part of the cable. 

EC60092-354 Part 354 Single- and three-core power cables with extruded insulation for... 

Conductor cross-sectional area (mm ) 1 Two-core cable, d.c. (mV/A/m) 2 Two-core cable, single-phase a.c. (mV/A/m) 3 Three- or four-core cable, three-phase (mV/A/m) 4... 

To convert an existing one-way switch control into a two-way switch control, a three-core and earth cable is run from the existing switch position to the proposed second switch position. The existing one-way switch is replaced by a two-way switch and connected as shown in Fig 14 7... 

Conductor Two-core Two-core cable, Three- or four-core... 

One cable system corresponds to six conductor systems composed of three cores and three metallic sheaths. As in the last section, the 6 x 6 impedance matrix of the cable system is represented by the following equation [1] ... 

Two cables Three or One two- One three- One two- One three- One two- One three-core... 

This approach was adopted for a study of polypropylene used as the filler in the interstices between the cores of some types of three-phase power distribution cables. The cores consisted of a conductor with polymeric insulation and extruded screens which were in turn screened with copper tape. Polypropylene twine is used to pack the interstices as the cable is laid up and then the outer parts of the cable are applied later. Thus the polypropylene is in direct contact with the copper tape. 

Table A16.23 Group rating factors for circuiis of three single core cables in trefoil and touching, horizontal formation laid directly ...

Table A16.26 Rating factors for variation in thermal resistivity of soil, three single-core cables laid directly in the ground (three cables in trefoil, touching)...

Note For many mining applications, this cable may additionally contain three (insulated) auxiliary conductors fitted into the core filler... 

Multi-core cables used for control, instmmentation, compnters and telecommunications carry very small currents in their conductors, when compared with power cables, and these currents feed into very sensitive electronic circuits. The system design of these electronic circuits must take account of interference that can be induced or circulated in the cable condnctors. Screens are provided around groups of typically two, three or four conductors, which are mainly intended to discharge static charges that can otherwise accnmulate and create noise or damage at the terminal equipment. Screens are also provided aronnd all the conductors in the cable for a similar reason. 

The startup detector assemblies (SDA) are fission chambers with the appropriate cabling and support structure. The SDAs are inserted into vertical channels in the reflector elements near the bottom of the core through three equally spaced penetrations in the bottom head of the reactor vessel. The SDA locations are shown in the plan view and vertical section of reactor core, Figures 4.3-5 and 4.3-6. The SDAs are interchangeable in any of the assigned locations. 

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