. Electrical world. d, «i, is given simul-taneously by the counter. The value of the formula above given isnot dependent on the time, and it is, therefore, of no importance forwhich period of time the values «i — ui and mi are taken; the onlycondition is that only values taken at the same time are to be com-pared. It is, therefore, not necessary, as in the case of the methodof illuminating the disc or with other methods of counting the pulsa-tions of current in the rotor, to record simultaneously the time, allthat is necessary being to count the numbers of passages of thesegments and read from
. Electrical world. d, «i, is given simul-taneously by the counter. The value of the formula above given isnot dependent on the time, and it is, therefore, of no importance forwhich period of time the values «i — ui and mi are taken; the onlycondition is that only values taken at the same time are to be com-pared. It is, therefore, not necessary, as in the case of the methodof illuminating the disc or with other methods of counting the pulsa-tions of current in the rotor, to record simultaneously the time, allthat is necessary being to count the numbers of passages of thesegments and read from the counter of the synchronous motor thenumber of revolutions during that time. The quotient of the firstvalue by the latter gives the slip of the motor. The simplest arrangement is that in which the disc of the syn-chronous motor and that of the induction motor have the samenumber of segments, and it is best to use for this number the numberof poles of the induction motor to be testedi In order to get actually. SLIP METER. the difference Ux — Ui, it is necessary to divide the observed numberof passages of the segments by the number of the segments on thedisc of the induction motor. If the slip is very large, the segmentsturn too quickly to make it possible to count the number con-veniently. In this case it is best to employ a disc with only onesegment; the observed number of passages is then equal to the num-ber of slipped revolutions. This involves another advantage com-pared with the method of counting the number of pulsations of cur-rent in the rotor. These poilsations follow each other so quicklyin the case of a large slip (commencing at about ) that they can-not be counted with any accuracy; with this new apparatus the num-ber of slipped revolutions can be counted directly by employingdiscs with only one segment. In order to obtain good results it isnecessary to place the synchronous motor at a greater distance fromthe induction motor than is shown in the illus
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectelectri, bookyear1883
