. Electrical world. , I, 2,and are so connected that the currentflowing through them produces a mag-netic flux closed in the iron frame as in-dicated by the arrows. The two sec-ondary windings are arranged concen-trically with the primary windings, Py. If the load in one of the twosecondary windings increases, then thiswinding will counteract its primarywinding with greater force; that is, itwill diminish the strength of the mag-netic flux so that the counter ofthe primary windings decreases. Forthis reason the network will now sendmore current into this primary winding, so that
. Electrical world. , I, 2,and are so connected that the currentflowing through them produces a mag-netic flux closed in the iron frame as in-dicated by the arrows. The two sec-ondary windings are arranged concen-trically with the primary windings, Py. If the load in one of the twosecondary windings increases, then thiswinding will counteract its primarywinding with greater force; that is, itwill diminish the strength of the mag-netic flux so that the counter ofthe primary windings decreases. Forthis reason the network will now sendmore current into this primary winding, so that the strength of theflux, common to the two secondary windings, is maintained. On ac-count of this automatic regulation, the voltage in the secondary wmd-ings is maintained constant.—Z(?i7. /. Elek. (Vienna), April 17. Electric Resistances of Bearings.—Dettmar.—.\ communication re-ferring to the recent letter of Zorawski and the former tests of Ken-nelly (see page 231, Electrical World and Engineer, February 7,. FIG. 3.—winding of single-phase ELECTRICAL WORLD and ENGINEER. Vol. XLIII, No. 19. 1903J. He has twice made a series o£ measurements of the resist-ance of bearings of electric machines and has always obtained re-sults which did not agree at all with each other. While he tested thefriction coefficient of various lubricating oils, he found that this co-efficient decreases with increasing speed of the machines, and in-creases again afterwards. The minimum point of friction corre-sponds to the moment when a continuous layer of oil has been the machine is at rest, this layer of oil is broken at the tried to determine the same minimum point by resistance meas-urements, but could not get any consistent results, since the values ofthe resistances varied greatly. An investigation whether the sort ofoil used had any influence did not yield any conclusive results, sinceno exact relations could be obtained. He sums up his experience inthe
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectelectri, bookyear1883
