GB190800177A - Improvements in Apparatus for Controlling Electric Motors - Google Patents

Abstract

177. Hindle, J. H. Jan. 3. Switches; motor control, systems; controllers for electric motors.-A compound-wound motor used for lift purposes after the manner described in Specification No. 26,098, A.D. 1901, has its field and armature circuits controlled by a barrel switch B and an automatic solenoid switch S<3>. The barrel is operated by two solenoids I, I', which are mounted in a common frame and have a common core with a rack which gears with a pinion on the barrel spindle. Two springs pulling on-opposite ends of an arm on the spindle reset the barrel in the' off' position. The solenoids may be energized from push-buttons, in which case an additional segment is provided on the barrel, which bridges two contacts in the push-button circuit only in the' off' position of the barrel, thereby rendering the push inoperative after the barrel has been moved. The solenoids are energized from a master switch MS in the cage through a flexible cable F, the current passing from the positive main through a terminal 1, a limit switch LS, the master switch MS, and through one of the solenoids I, I' to the negative main. The armature terminals are led to two pairs of connected contacts A', A<2>, other pairs of contacts All, A<22> also connected in pairs serving as terminals for two resistances SCR both of which are in parallel across the armature in the 'off' position. One of the solenoids having pulled the barrel to the right, a circuit may be traced from the negative main through resistances R', R<2>, a solenoid S<5>, and series windings S to a contact S<2>; thence to a contact A<1> through the armature to an upper contact A<2>, and to a contact connected to the positive main. As the current through the coil S<5> weakens, the core drops and cuts out the series windings. The current path for the shunt windings leads from the resistance R<2> to the switch T' and contacts h, h<1>, and through the windings Sh, to the contact Sh<2>. A resistance R<3> is inserted in this path by the tripping of the arm T<1> when the contacts SCC have reached the upper limit of their travel. A solenoid S<4> may, however, be energized to keep the resistance R<3> short-circuited, thereby causing a stronger field and slower rotation of the armature.