Table Of Content

Z _^JL Class Book 'f~'/ (7?¥ n siht Electrical Engineer's pocket-book: A BAND-BOOK OF USEFUL DATA FOR ELECTRICIANS AND ELECTRICAL ENGINEERS. BY HORATIO A.| FOSTER, Fellow A.I.E.E.; Mem.A.S.M.E. Consulting Engineer. Author of "Engineering Valuation of Public Utilities and Factories." Withthe collaborationof eminentspecialists. SEVEJVT^f^Qf^p^ HEVISED mymm£nTpnm r FOR OFFIQA^JJSE C ACCOUNTED FOR IN tfKBfcwiTH PAR. 693 A. h. NEW YORK: D. VAN NO-STRAND COMPANY 1918. Copyrighted, 1902, 1908, 1913, by VAN NOSTRAND COMPANY, D. New York. 3IHT gj By Exchange Mlddtetown DepotSupply March 10,188! -4 r ^ PREFACE TO THE FIFTH EDITION. £ In appreciation of the very cordial receptionaccorded the earlier editions of this book, and in recognition of the fact that vast changes and advances have occurred in every branch of electrical engineering since the original publication, the author feels called upon to issue the present revised and enlarged edition. The book as now presented, exceeds the previous editions in magnitude by about 600 pages, while the subject matter of every section has been either com- pletely revised and brought up to date, or entirely re-written. The aim throughout has been to supply in exhaustive and condensed form, the data essential to the engineer engaged in any of the branches of the vast domain of electrical engineering. While our concep- tion of the fundamental principles of electrical science can of necessity have undergone no very considerable alteration, those esse&ttal details which in effect con- stitute thet^working -data .Qf the practicing engineer have so altered and g^wn that books published only : a few years ago are already obsolete. It is believed that a stage in the progress of electrical engineering standardization has now been reached wherein a com- pilation such as the present can be accepted as embody- ing the vital element to which future advmces will appear to a degree in the relation of superficial alter- ations. The original plan of dividing the subject into a number of sections and having each revised by an iii iV PREFACE TO THE FIFTH EDITION. eminent specialist in that particular field has again been followed. Aside from the easy accessibility afforded, this plan of construction is valuable only in proportion to the weightiness of the authorities entrusted with the revision of the several divisions, and it is confidently believed that a perusal of the names heading the sections will lead to the conviction that a more approved and authoritative organization could not have been wished for. The several contributors are widely known and recognized as among the first of their respective specialties, and it is believed that the general average of excellence assured by their collaboration surpasses that of any compila- tion of the kind previously attempted. Each section is complete in itself, but needless repetition has been avoided by the free use of cross references through the medium of the very extensive index. Attention is directed to the large quantity of new matter, appearing for the first time in print, in the several sections. In the section on Conductors, e.g., the tables of Inductance, Capacity and Impedance, will be found new and original. Many sections, e.g., Street Railways, Photometry, Conductors, Lighting, Roentgen Rays, etc., are pointed out as examples of exhaustive though condensed presentation. The mechanical section has been treated with the same care and attention as the electrical. The matter has been confined to the requirements of the electrical trades and sciences, the inclusion of the usual mathematical tables and data found in the commonly used handbooks having been avoided. These tables being easily accessible, and the present PREFACE TO THE FIFTH EDITION. V edition being already of great magnitude, this exclu- sion will be appreciated. An important feature of the present volume will be found in the voluminous and studiously developed index and table of contents. The index is as complete as the limitations of manipulative facility will permit, and is calculated to render the finding of the particular phase of the subject sought a matter of least possible labor. The table of contents is designed to supplement and extend the use of the index, and in conjunction with the marginal thumb-index will render instantaneous the location of sections and subdivisions. The careful and lengthy work of revision and search leads the author to believe that the number of errors cannot be large, and he ventures to express the hope that readers discovering any will have the kindness to bring them to his attention. In conclusion the author begs to express his grati- tude to the many contributors for their cooperation, and to the publishers for their painstaking effort and generosity in making so handsome and substantial a volume. HORATIO A. FOSTER. 100 Broadway, New York. June 1, 1908. PREFACE TO THE SEVENTH EDITION. No attempt has been made in this edition to add new matter nor to make radical changes in the old, but in a few cases substitution has been made, as in the latest revision of the Standardization Rules of the Am. Inst. E. E., and some changes in the text and cuts in the chapter on Switchboards. A number of typographical and other errors have been corrected. HOEATIO A. FOSTER. 43 ExchangePlace, New York, April 1, 1913.