GB605721A - Control apparatus for controlling the operation of drive means for placing a useful load in a desired position - Google Patents

Abstract

605,721. Electric follow-up systems. YARDENY, M. N. Aug. 24, 1945, No. 21798. [Class 40 (i)] In a follow-up system employing coarse and fine follow-up switches, means are provided for disconnecting the fine follow-up switch while the coarse switch is controlling the follow-up motor. Fig. 1 shows an arrangement in which coarse and fine follow-up switches II and I actuate split field series motor 2 when their " stators " 20 and 10 are displaced with respect to their rotor arms 21 and 11 by means of friction drive knobs 38<SP>x</SP> and 48<SP>x</SP>. Initially, the motor takes current through relay 72 and follow-up switch II, the former isolating switch I, until switch II has been driven to approximate correspondence, when relay 72 is de-energized and fine switch I takes over control of the motor. Resistors 4 and 5 are provided to reduce the motor speed when switch I controls it and to prevent the motor being stopped by the equal energization of field windings 6 and 7 which would otherwise occur each time rotor 11 bridged gap 19<SP>1</SP> when switch II was in control. Selectors I<SP>1</SP> and II<SP>1</SP> may be utilized by closing switch A<SP>1</SP> instead of switch A. Pairs of relays may be interposed between the switches and the motor, as in Fig. 2 (not shown), or, as in Fig. 3 (not shown), a single pair of relays may be used to control a shunt motor. Fig. 4 shows an alternative linear follow-up switch in which the motor moves rod 79 carrying contact segments 86, 87, co-operating with adjustable and fixed contacts 81<SP>x</SP> and 24, 25. The arrangement of Fig. 2 may be further modified, as in Fig. 5 (not shown), by using relays having double armatures, the second pair being used instead of relay 72 in the case of the pair associated with switch II, and for cumulatively energizing the other motor field winding in the case of those associated with switch I. Fig. 6 shows an arrangement for use when a number of pairs of preset switches are used, the relay 172 replacing relay 72 and being provided with contacts 162 in the circuit of switch II, the movement being started by depressing a push-button 170 bridging the contacts. The Figure also shows a modified switch in which additional gaps 26<SP>x</SP> and 27<SP>x</SP> are made in the contact segments.