Abstract: The invention relates to a method of controlling two or more commutator DC motors with permanent magnets in driving mechanisms for setting a position of furniture parts such as tables, beds, chairs etc., where particular driving mechanisms must maintain mutually defined speed independently on their different load. The invention consists in that during functioning of the motors is periodically disconnected power supply of the motors, while in the time of disconnecting the supply is detected the voltage of each motor, which is adjusted using calibration constant characteristic for each motor and the direction of rotation and according to the differences of such adjusted voltages of particular motors is adjusted the operating mode of each motor, by means of which is reached an effective regulation of particular motor run to mutually defined speed independently on their load.

Abstract: In an electrical power system of a diesel powered system having at least one diesel-fueled power generation unit, the electrical power system having a synchronous machine including a field winding being coupled to the diesel-fueled power generation unit, a battery for selectively providing a starting current during a starting mode of the electrical power system, and an inverter receiving the starting current for driving the synchronous machine and generating an inverter current, a circuit and method for reducing a voltage being developed across the field winding is described. The circuit includes a current conditioner for conditioning the inverter current and a parallel circuit interposed between the inverter and the current conditioner comprising a first branch including a resistance and a second branch including the field winding of the synchronous machine so that the parallel circuit is isolated from a voltage developed across the current conditioner during cranking.

Abstract: A method and system that provides for simultaneous or independent start-up of two or more three-phase AC motors with reduced starting current. Two AC motors have their stator windings connected in series across the power network. If more than two AC motors are to be started, the stator windings of the additional motors are connected in parallel with the stator windings of one or both of the first two motors and the phase leads of the additional motors are connected to the power network. The voltage result vector is less than the sum of the rated voltage of each motor. After a preset time delay or when the motors reach a certain speed, the rated voltage is applied to each motor by disconnecting the stator windings from the series connection and connecting the stator windings of each motor in a delta configuration.

Abstract: A system, which may be a cooling system for a motor vehicle engine, has two direct current motors together with switching circuits which provide selective connection of the windings of the two motors to a direct current voltage source in such a way as to obtain different operating modes for each motor. One of the motors has four brushes, the first of which is permanently connected to the first polarity of the source, while its second, third and fourth brushes are arranged so that they can be connected to the appropriate source polarities respectively through either three interruptors or two. The second motor has two brushes permanently connected, respectively, to the same first source polarity and to the third or fourth brush of the first motor.

Abstract: In a drive system for a grinding mill the load torque plus frictional torque may increase considerably as a loaded mill is inched from its rest position and will suddenly decrease when the load tumbles or cascades. The applied torque or driving torque must increase at a corresponding rate and should also decrease when the load cascades. If the applied torque exceeds by a significant amount the load torque plus frictional torque, a destructive hammering will occur in the gear train and this will be generally proportional to the excess of applied torque for a synchronous motor drive. The drive system has a DC source which is commutated by a commutating device to provide a low frequency stepped alternating voltage to the stator windings of the synchronous motors of the drive system for inching. The output of the DC source has an alternating current component which varies as the difference between the applied torque and the load torque plus frictional torque.