| 摘要 |
466,819. Master control of D.C. motors. GENERAL ELECTRIC CO., Ltd., CROFT, E. H., and PYE, J. F. Dec. 10, 1935, No. 34193. [Class 38 (iii)] In a series-parallel control system, provision is made for effecting a series connection of the motors, a parallel connection, a connection in which the parallel circuits are completed independently of series control resistances and their control switching means, and a parallel connection in which the resistances serve for field weakening, the several circuit connections of the motors being effected by two two-position switch groups adapted to be relatively positioned in like and unlike positions, and two of the circuit connections including contacts of the two groups series-connected. When a master controller is moved to a first series position lines switches LS1, LS2, close, and, the two two-position switch groups being in their " off positions the contacts S1A, S1B, are closed, so that the motors 1, 2, are connected in series across the supply in series with respective armature resistances 9, 10. Contacts 11-14 are then closed in steps to cut out the resistances 9, 10 in steps under the control of a current limit relay 58 and, at the completion of this stage, a series contactor S2 is closed to cut out terminal portions 60, 61, of the resistances 9, 10, and exclude the resistances independently of the contacts 11-44. When the master controller is moved to a full parallel position the contacts 11-44 are opened and one of the two two-position switch groups is operated to its " on " position. Contacts S1A, F1A, F2A, are thereby opened and contacts P1A, P2A, closed. The series contactor S2 then opens and the motors 1, 2, are connected in parallel across the supply each in series with its armature resistance 9, 10. The contacts 11-44 again close to remove the resistances 9, 10, in steps and the other of the two two-position switch groups then operates to open contacts S1B and close contacts P3B, P4B, F1B, F2B. The contacts P3B, P4B, bridge resistances 9, 10 and the contacts P1A, P2A. The contacts 11-44 again open and, when the master controller is moved to a first weak field position the first-operated of the two two-position switch group returns to its " off " position to open contacts P1A, P2A, and close contacts F1A, F2A, S1A. Thus the resistances 9, 10 are connected each in series with a resistance 45 or 46, across the field 3 or 4 of its respective motor. In the weak field position of the master controller the contacts 11-44 are again closed under control of the current limit relay to remove the resistances 9, 10, in steps. A trip coil may be provided for effecting operation of an overload relay which controls the line switches LS1, LS2, and a normally open contact of the overload relay may control a test relay whereby the various switch groups may be tested as described in Specification 466,285. |
