Abstract: A voltage to be applied to the primary winding of a drive motor is automatically and time-functionally adjusted in relation to the rated voltage of the drive motor in order to provide sufficiently large torque for beating during the starting period of the loom running and transit to normal running of the loom is carried out at a preselected moment other than the moment of beating motion. Change in voltage is effected through either switching in mode of connection for the primary winding or transforming the power source voltage which is maintained constant.
Abstract: A pole amplitude modulated electric machine is operated at continuously variable speeds between fixed limits by a control circuit which rapidly switches the stator winding between the upper and lower pole number configurations. The switching is controlled such that the stator winding remains in each configuration for a time which exceeds the cycle time of an external power source but is less than the combined magnetization-rotor loop time constant of the machine. Phase control of the switching can be used to control speed in the vicinity of the fixed limits. In all cases, the input power frequency remains constant.
Abstract: Method and apparatus for matching the power output of a high slip motor to the demand requirement of a pumpjack unit. The stators of the high slip motor are automatically connected in various different configurations to provide the optimum torque as required by the pumpjack unit due to the downhole pumping condtions. A novel control circuitry is connected between the motor starter and the motor stators. The control measures the power drawn by the stators and selects the most optimum configuration thereof for the load required by the pumpjack. This selection operates the motor in the lowest possible torque mode, which is considered the best electrical and mechanical operation of the pumpjack apparatus.
Abstract: A circuit comprising a load sensor connected to a multiple rated motor for monitoring the motor load demand and a switching apparatus connected to the source of electrical power for changing the connection of electrical power to the windings of the motor under load in response to the motor load demand.
Type:
Grant
Filed:
October 8, 1982
Date of Patent:
February 28, 1984
Assignee:
Westinghouse Electric Corp.
Inventors:
Walter J. Kellogg, Arden L. Scott, Samuel K. Seneadza
Abstract: A control system is disclosed for connecting the primary windings of a three-phase AC inducton motor in a delta-connection at heavy loads and for automatically reconnecting the windings in a wye-connection at light loads to effect energy savings. Power sensing means produces a control signal which is directly proportional to the power applied to the induction motor. Differential comparator means respond to the control signal and to an adjustable reference signal, representing a preselected power input level, for generating an actuating signal for switching a wye-delta starter between two conditions, one of which effects the wye connection and the other the delta connection. When the power input is below the preselected level the wye-connection is established, whereas the delta-connection is made when the power input is above the preselected level.
Abstract: Method and apparatus for matching the power output of a multitorque motor with the torque requirement of a connected load device. The stator windings of the motor are automatically connected in various different configurations to provide the optimum motor torque demanded by a connected load device which imposes varying load conditions on the motor. A novel control circuitry is connected between the motor starter and the motor stators. The control measures the power drawn by the motor stators and selects the most optimum configuration thereof which meets the changing torque requirements of the connected load device. This selection of optimum stator winding configurations commensurate with torque demand operates the motor in the lowest possible torque mode, which is considered the best electrical and mechanical operation of the motor and connected load device.
Abstract: An electric brake motor, particularly of the kind having a squirrel cage rotor and a slow-running stator winding with a large number of poles, is provided with electrical switching means to increase the motor current briefly on starting, at least on starting of the slowrunning winding, so as to increase the magnetic field generated by the motor current for releasing the brake. The switching means may be contacts actuated by axial movement of the rotor on starting, or a relay or contactor operated by the motor current or by a control switch. The increase in current may be achieved by briefly shortcircuiting part of the motor winding or by briefly connecting a second, fast-running stator winding in parallel with the slow-running winding in the case of a change-pole motor.
Type:
Grant
Filed:
April 30, 1979
Date of Patent:
July 7, 1981
Assignee:
R. Stahl GmbH & Co.
Inventors:
Rudolf Uhrner, Klaus Teuke, Wolfgang Schwarz