Electrical news and engineering . pointed out that enclosed motors are desir-able, to keep chips out of the interior of the motor. In somesevere cases pipe-ventilated or drip-proof types are neces-sary. The Development of Reversing Tool Drive The old-fashioned method of mechanical driving ofplaners and such tools by means of two belts and a beltshifting gear is both wasteful and unsatisfactory and offersconsiderable scope for improvement. The use of a reversingmotor whose direction is controlled by the moving head isan obvious step; the addition of a motor generator of whichthe direction and s
Electrical news and engineering . pointed out that enclosed motors are desir-able, to keep chips out of the interior of the motor. In somesevere cases pipe-ventilated or drip-proof types are neces-sary. The Development of Reversing Tool Drive The old-fashioned method of mechanical driving ofplaners and such tools by means of two belts and a beltshifting gear is both wasteful and unsatisfactory and offersconsiderable scope for improvement. The use of a reversingmotor whose direction is controlled by the moving head isan obvious step; the addition of a motor generator of whichthe direction and strength of the generator field are so con-trolled is a marked improvement on that method. There have been some interesting developments in thisfield. (Jne English manufacturer commencing with a revers-ing motor, geared directly to the planer table, graduallyevolved a slip-ringless magnetic clutch which, it is claimed,offers considerable advantages over the direct drive. Forinstance, the amount of stored energy to be dissipated at. Electrical equipment for planer. Complete conversion and control ofrent. Photograph courtesy Alfred Herbert, Ltd. .\ \ariable speed motor cost;, more than the equivalent con-stant motor which would lie used for the same machine extra cost when taken as a percentage of the completecost of the machine-tool e(|uii)mcnt would, however, besmall. The speed range obUiinable on the motor itself en-aliles the nuichine-tiKil maker lo dispense with a gear boxaltogether in some instarjccs, and reduce the number of .gearratios in others. The wearing parts of the machine tool aretherefore reduced. In addition, very fine speed incrementsii\er a wide range can be obtained, as against the definitenumber of speeds oljtained with mechanical A variable speed motor geared direct to the machinetool, enables the highest economical cutting speed to beeasily and quickly found by the operator. The increasedoutput resulting from the delicate speed
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Keywords: ., bo, bookcentury1800, bookdecade1890, bookidelectricalnewsen31donm
