TransactionsPublished under the care of the General Secretary and the Treasurer . 8 Stator Core #2. Rotor Core #2. Air Gap =.5~ I Three phase 4 pole winding on Stator and Rotor II Stator 3 phase 4 pole; Rotor 6 phase 4 pole III 12 one slot per pole per phase IV Three phase 8 pole winding on Stator and,RotorV V 16 VI Stator 3 phase 16 pole; Rotor made into squirrel cage with bars hayingsame location in slots as former winding. Fig. 13. Another test was made with the rotor connected two-phase, theresult being just what was predicted, an average increase of beltreactance, but a m
TransactionsPublished under the care of the General Secretary and the Treasurer . 8 Stator Core #2. Rotor Core #2. Air Gap =.5~ I Three phase 4 pole winding on Stator and Rotor II Stator 3 phase 4 pole; Rotor 6 phase 4 pole III 12 one slot per pole per phase IV Three phase 8 pole winding on Stator and,RotorV V 16 VI Stator 3 phase 16 pole; Rotor made into squirrel cage with bars hayingsame location in slots as former winding. Fig. 13. Another test was made with the rotor connected two-phase, theresult being just what was predicted, an average increase of beltreactance, but a much-reduced variation of total reactance, due tothe shorter belt cycle. The experimental results considered above show clearly that evenin the case of 3-phase, 60 cycle motors, the belt reactance playsan important part in the variation of the total reactance with rotorposition, and that in the case of lower frequencies it becomes stillmore prominent. Therefore if a reasonably-accurate measure of the leakage re-actance is desired, an average should he talen over the belt Fig. 14.— Experimental motor. I — 7-23 ADAMS: LEAKAGE REACTANCE OF INDUCTION MOTORS. 723 Table II shows the interchange of relative importance betweenthe several leakage elements as the frequency changes; it is basedupon rotor Xo. 1 and stator No. 1 with normal gap, and assumesthat the same cores are wound for the several frequencies in such away as to keep the same peripheral velocity. Table II. oc 3 i Ohms reactance on arbitrary basis. Per cent of total reactance. Slots. Coilends. Averagetoothtip. Averagebelt. Total. Slots. Coilends. Average tooth tip. Averagebelt. 603015 163264 7*13* . 32 These would be 9 and 18 respectively were it not for the larger number of slots perpole per phase as the frequency decreases. Such a change of frequency without other changes does not rep-resent good design, but the table gives the correct general i
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