公开(公告)号：US3584278A

公开(公告)日：1971-06-08

申请号：US3584278D

申请日：1968-11-25

Applicant: ASEA AB

Inventor： KRABBE ULRIK

IPC: B66C13/26 ,  H02P3/24 ,  H02P23/00 ,  H02P25/20 ,  H02P27/02 ,  H02P1/38

CPC classification number: H02P27/026 ,  B66C13/26 ,  B66C2700/081 ,  H02P3/24 ,  H02P23/24 ,  H02P25/20 ,  H02P27/02

Abstract: A driving system for cranes includes a three phase asynchronous motor with a squirrel cage rotor and two stator windings with different numbers of poles. The speed is steplessly controllable within a lower speed range below the synchronous speed corresponding to the higher number of poles in response to the difference between actual and desired speed. This difference quantity passes unidirectional means which, depending on its sign, feeds it as a control signal to a delay angle current varying device inserted between the low speed stator winding and the network, or to a controlled DC source which, during operation in the lower speed range, is connected to the high speed winding, that is, the stator winding with a lower number of poles. This winding is by means of a throwover switch also connectable to the network, in which case the signal circuit of the delay angle current device is intended to be broken by means of a signal current breaker so that no current is fed to the low speed stator winding.

公开(公告)号：US3430122A

公开(公告)日：1969-02-25

申请号：US3430122D

申请日：1966-04-15

Applicant: ASEA AB

Inventor： KRABBE ULRIK ,  HEDSTROM HANS

IPC: H02P27/02 ,  H02P1/40 ,  H02P3/20 ,  H02P5/28

CPC classification number: H02P27/026

公开(公告)号：US3566248A

公开(公告)日：1971-02-23

申请号：US3566248D

申请日：1969-01-24

Applicant: ASEA AB

Inventor： KRABBE ULRIK

IPC: H02M5/27 ,  H02M5/16

CPC classification number: H02M5/271

Abstract: A FREQUENCY CONVERTER FOR CONVERTING AN ALTERNATING VOLTAGE OF A HIGHER FREQUENCY TO AN ALTERNATING VOLTAGE OF A LOWER FREQUENCY, THE CONVERTER INCLUDING AT LEAST TWO GROUPS OF MUTUALLY COMMUTATING RECTIFIERS, IS CONTROLLED BY A PILOT VOLTAGE GENERATOR WHICH GENERATES A VOLTAGE HAVING THE DESIRED AMPLITUDE AND FREQUENCY OF THE OUTPUT VOLTAGE OF THE CONVERTER. THE PILOT VOLTAGE IS COMPARED WITH A REFERENCE VOLTAGE DERIVED FROM THE INPUT VOLTAGE OF THE CONVERTER. THE COMPARISON IS USED TO GIVE THE DESIRED CONTROL ANGLE FOR THE RECTIFIERS IN EACH GROUP. THE CONTROL MEANS FOR EACH RECTIFIER INCLUDES AN INTEGRATING ARRANGEMENT INCLUDING A MEMORY DEVICE CONSTITUTED BY A CAPACITOR AND SWITCHING MEANS CONSTITUTED BY TRANSISTORS CONTROLLED BY THE INPUT VOLTAGE OF THE CONVERTER TO CONNECT THE MEMORY DEVICE ALTERNATELY TO THE PILOT VOLTAGE GENERATOR AND TO THE CONTROL CIRCUIT FOR THE RECITIFIER AT A RATE CORRESPONDING TO THE PERIOD LENGTH OF THE INPUT VOLTAGE DIVIDED BY THE PULSE NUMBER OF THE COMMUTATING GROUP.