Handbook of Electrical Engineering

EARTHING AND SCREENING 369 Annex A of BS7430 gives formulae for various shapes of buried conductors. See also Appendix H of Refe ...

370 HANDBOOK OF ELECTRICAL ENGINEERING per-unit or percentage factors that relate to the grid geometry. These are then used to s ...

EARTHING AND SCREENING 371 13.4 Construction Details Relating to Earthing This section describes some of the practical construct ...

372 HANDBOOK OF ELECTRICAL ENGINEERING Cubicles and light duty terminal or junction boxes often use stainless steel or painted m ...

EARTHING AND SCREENING 373 with a very rapid fall in potential just inside the insulation (measured or defined in volts/mm). The ...

374 HANDBOOK OF ELECTRICAL ENGINEERING a) Single conductor above a flat plane. Leakage capacitance. Self-inductance. b) Two cond ...

EARTHING AND SCREENING 375 Figure 13.13 Mutual coupling between spaced out cables. In these examples the situation of interest i ...

376 HANDBOOK OF ELECTRICAL ENGINEERING Figure 13.14 Interference and screening circuit of cables that are run in parallel with e ...

EARTHING AND SCREENING 377 FindIcin terms ofI 3. AssumeVin=0 in order to determine the amount of current induced fromI 3. Let th ...

378 HANDBOOK OF ELECTRICAL ENGINEERING This has the form:- y 2 =a 21 Ic+a 22 Is ( 13. 11 ) Where y 2 =−jωM 3 sI 3 a 21 =+jωMsc a ...

EARTHING AND SCREENING 379 If the cable core terminates at a high impedance device such as the input channel of an operational a ...

380 HANDBOOK OF ELECTRICAL ENGINEERING Figure 13.15 Interference and screening circuit of cables that are run in parallel with e ...

EARTHING AND SCREENING 381 Figure 13.16 Holes in the braided armouring of instrumentation cables. This impedance can be used to ...

382 HANDBOOK OF ELECTRICAL ENGINEERING a) Switchboards and motor control centres It is the normal practice to provide a copper b ...

EARTHING AND SCREENING 383 References 1.IEEE Guide for safety in AC substation grounding. ANSI/IEEE Std 80–1986 Library of Congr ...

14 Variable Speed Electrical Drivers 14.1 Introduction Due to an increasing concern about conserving energy there has become a r ...

386 HANDBOOK OF ELECTRICAL ENGINEERING DC motors have a widely variable drooping torque versus speed characteristic and so, for ...

VARIABLE SPEED ELECTRICAL DRIVERS 387 switchboards, other driving motors. Hence the voltages throughout the system will be conta ...

388 HANDBOOK OF ELECTRICAL ENGINEERING 14.2 Group 1 Methods In this group there are three alternative possibilities that are pra ...

VARIABLE SPEED ELECTRICAL DRIVERS 389 Figure 14.1 Variable applied voltage with a normal design of an induction motor. the same ...