Design of a universal portable electric drill . HIGURE 17 entirely too high but experiencewith this tsrpe or machine equippedwith their very efficient ventila-tion proves this to he a conserva-tive ligure. uur armature will, therefore,be wound with SO coils, each coilconsisting of 12 turns of No. 24wire. The coils will he woundand taped in pairs giving 15douhle coils end 48 wires perslot. The connection to the commutator v;ill he as shown in^igure 16. The limit to the speed of the armature is apt to be thecommutator peripheral speed. Practical considerations make itdifficult to build a 30 segm
Design of a universal portable electric drill . HIGURE 17 entirely too high but experiencewith this tsrpe or machine equippedwith their very efficient ventila-tion proves this to he a conserva-tive ligure. uur armature will, therefore,be wound with SO coils, each coilconsisting of 12 turns of No. 24wire. The coils will he woundand taped in pairs giving 15douhle coils end 48 wires perslot. The connection to the commutator v;ill he as shown in^igure 16. The limit to the speed of the armature is apt to be thecommutator peripheral speed. Practical considerations make itdifficult to build a 30 segment commutator of diameter smallerthan that shown in Figure 17. The insulation between bars and the width of segments showncannot be materially reduced without danger from shorts andoverheating. Regardless of the limits set by designers oflarge machines the peripheral speed of the commutators on thisclass of motor may be as nigh as 5500 feet per minute when themotor is running idle. On this basis the speed of this machineat rated load would be
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Keywords: ., bookcentury1900, bookdecade1920, booksubjecttheses, bookyear1920
