Patent GB-190823111-A (GB)
Title: Improvements in the Method of and Apparatus for Controlling Electric Cranes.
Inventor: HOLME EDWARD MORTEN
Filed: 1908-10-30
Granted: 1909-09-02
Abstract: 23,111. Holme, E. M. Oct. 30. Motor controllers ; switches. - The main controller for the electromotors of a crane is operated by means of solenoids or electromagnets controlled from a portable switchboard carried by the attendant or placed in different places for use at different times, the connexion between the main controller and the portable switch being made by flexible leads or jointed conductors. In the arrangement shown in Fig. 1, the main leads + M, - M supply current through the main controller coils RSS and field F of the motor to its armature A. The controller coils are cut out successively stepby-step by switches operated by solenoids 16 ... 20, which receive current from leads + SS, - SS, which may be of lower voltage than the supply mains. The solenoids 16 ... 20 are connected to a portable switchboard PS through a flexible or jointed cable FC. If the contact 1 is moved one notch counter-clockwise from the "off" " position shown, it connects contacts 2, 3, 4, thus energizing one solenoid of the reversing - switch and the solenoid 16, and throwing the whole of the resistanbes RSS into the circuit. If moved two notches, the contact 5 is reached and the solenoid 17 energized, thus cutting out the first resistance. Similarly, on the contacts 6 ... 8 being reached, the solenoids 18 ... 20 cut out the remaining resistances. If the movable contact 1 be moved in the clockwise direction, at the first notch the contacts 9 ... 11 are connected, the solenoid 16 and the other solenoid of the reversing - switch being energized. Further movement of the contact 1 energizes solenoids 17 ... 20 and cuts out the resistances. For safety, the several resistance switches may be electrically interlocked with the reversing-switches, so that the latter cannot operate unless all the resistance switches are " open." Fig. 2 shows a modification applied to a controller of the drum type. The solenoids 21, 22 are provided with racks engaging a pinion on the controller spindle, which is fitted with a spring or weight attachment tending to bring it to the " off " position. Two arms 51, 50, carried by the spindle, are provided with catches to engage any of the spring stops 39 ... 43, which are thrown into position to hold the arms by means of solenoids 24 ... 28. Leads + SS, - SS supply current to the solenoids 21, 22 and to the solenoids 24 ... 28, both sets of solenoids being connected up to the portable switchboard PS. A contact arm 70, 71 on the portable switchboard has its spindle 72 connected to the negative lead, while the contact strips 83, 84 are connected to solenoids 22, 21. The contacts 73 ... 77 and 78 ... 82 are connected to the solenoids 24 ... 28. When the arm 70, 71 is turned clockwise to engage the contact 73, the solenoid 24 is energized, and the stop 39 drawn into the path of the arm 50, which it locks in position. In the next position of the arm 70, 71, the contact 74 is engaged, and the solenoid 25 energized, the solenoid 24 becoming de-energized. The arm 50 is now locked by the stop 40, and so on. On moving the arm 70, 71 in the opposite direction, the contacts 78 ... 82 energize the solenoids 28, 24 for the engagement of the arm 51 in the reverse movement of the motor. The solenoids 21, 22 may be replaced by small motors geared to the controller spindle. A main switch arranged in the motor circuit is operated from the portable switchboard for making or breaking by means of a solenoid, and is electrically interlocked with the resistance switches so that it cannot complete the circuits unless all the resistances are in. Fig. 5 shows such a switch 94 carrying below it the interlocking switches. The solenoid 91 is connected to the - SS lead and also to contacts 96, 98. The contact 97 is connected to contacts 126, 127, &c. of the resistance solenoids, which contacts are connected by the insulated conductor 123 when the solenoids are de-energized. The lead 130 is connected through a switch on the portable switchboard to. the + SS and is also connected to the contact 99. If now the switch is moved to its "on" position, the solenoid 91 cannot be energized unless the resistance solenoids 120, 121 are de-energized.