GB603723A - Improvements in electrically-driven web-winding equipment - Google Patents

Abstract

603,723. Automatic control systems for winding equipment. MASON, F. R., and METROPOLITAN-VICKERS ELECTRICAL CO., Ltd. Aug. 30, 1945, No. 22373. [Class 38 (iv)] In web-winding equipment, constant linear speed of the web is maintained automatically, by control of the motor and associated generator excitations. The web W is wound on reel B by the D.C. motor D, the armature DA of which is in series with armature GA of generator G, driven by three-phase motor M from supply mains L. Separately excited fields DF, and GF of motor D and generator G respectively, are in series with constant voltage exciter E. A metadyne exciter A is connected across the field GF with the control excitation provided by opposing fields AR, in parallel with rheostat R across exciter E, and AV, supplied from tachometer generator T, the output of which is a measure of the web speed being driven therefrom. The armatures of generators E and A are driven from motor M. Closure of push-button S starts motor M, by energizing contacted coil CC, to close contacts C, in line L, and the holding contact CA. A normally closed stop switch breaks both of these circuits. Contact RI is closed so as to permit starting-up of motor M only when rheostat R is in the position of minimum reference voltage across field AR. The winding operation is commenced by closure of contacts C to start motor M and generator G. Initially, the voltage generated by metadyne A is zero, the armature AA effectively short-circuits field GF, and the output voltage of exciter E is applied to the field DF. Operation of rheostat R to increase the metadyne excitation, and consequently the output voltage, raises the voltage applied to the field GF and reduces that across field DF. Reel motor D starts and the speed rises progressively as rheostat R is operated. At the desired speed the opposing fields AV, AR balance substantially and as the radius RR increases the tachometer generator T speed rises and thus raises the excitation of field AV, reduces the excitation of field GF and raises that of DF so lowering the speed of reelmotor D to ensure constant linear speed of the web. An electromagnetic brake, applied to reel driving motor D, is released on the supply being made to motor M.