Abstract: A steering control apparatus includes a direct current power source, a three-phase alternating current motor, and a motor driving circuit. An emergency switching element is provided on at least two phases of a three-phase power supply line connected to the three-phase alternating current motor within the motor driving circuit, and the emergency switching element is turned off when an abnormality occurs such that the motor driving circuit is disconnected from the three-phase alternating current motor. The emergency switching element is a MOSFET, and the MOSFETs are provided in pairs in each of the two phases of the three-phase power supply line. Further, parasitic diodes of the pairs of MOSFETs are disposed in opposite orientations to each other.

Abstract: An electric power steering apparatus for assisting the steering force of a steering member by an electric motor (18) driven by a driving circuit (13) connected to a power supply (P) by power connecting means (15a). The electric power steering apparatus comprising: means (12) for detecting a short-circuit failure on the driving circuit (13) and on a wiring connecting the driving circuit (13) and the electric motor (18); power off means (15) for turning off the power connecting means (15a) when a short circuit failure is detected; current detecting means (17) for detecting the value of a current flowing between the electric motor (18) and the driving circuit (13) after the power off means (15) turns off the power connecting means (15a); and current cutting means (Fa, Fb) for, when the current detecting means (17) detects a current value exceeding a predetermined value, irreversibly cutting off the current whose current value exceeds the predetermined.

Abstract: In order to raise the drive efficiency of a spindle motor that drives a recording disk for information recording and hence to achieve power saving/lowering of noise level of the information recording device as a whole, in an information recording device wherein a synchronous motor is employed as the spindle motor that drives the recording disk for information recording, and wherein the head is accessed for purposes of reading or writing information at a designated position on the recording disk, with change in mechanical output of this spindle motor, the mechanical output value sought for the spindle motor is found from the head position on the recording disk before and after access, and the thus-found mechanical output value is used to adjust the electrical input to the spindle motor.

Abstract: The apparatus positively induces synchronism in at least two lifting jacks. It has an upwardly and downwardly movable carriage, on the lifting jack, a column, a lifting device extending along the column, a first control device to control the lifting device in the "lift" direction, a second control device to control the lifting device in the "lower" direction, a "lift" switch on the main lifting jack, a "lower" switch on the main lifting jack. For each lifting jack, a motor device acts on the lifting device. Along each column there is an equally spaced marking unit, the spacing corresponding to the maximum admissible lift difference between the lifting jacks. Each marking unit has an `ON` zone and an `OFF` zone. Rigidly fixed to each carriage is a tracer for scanning the marker units. Each tracer, is in an electrical switching device, and inhibits the motor device when the tracer is in the `OFF` zone, until such time as the tracer of the carriage which is lagging most behind is also in the `OFF` zone.

Abstract: The apparatus positively induces synchronism in at least two lifting jacks. It has an upwardly and downwardly movable carriage on the lifting jack, a column, a lifting device extending along the column, a first control device to control the lifting device in the "lift" direction, a second control device to control the lifting device in the "lower" direction, a "lift" switch on the main lifting jack, a "lower" switch on the main lifting jack. For each lifting jack, a motor device acts on the lifting device. Along each column there is an equally spaced marking unit, the spacing corresponding to the maximum admissible lift difference between the lifting jacks. Each marking unit has an `ON` zone and an `OFF` zone. Rigidly fixed to each carriage is a tracer for scanning the marker units. Each tracer, is in an electrical switching device, and inhibits the motor device when the tracer is in the `OFF` zone, until such time as the tracer of the carriage which is lagging most behind is also in the `OFF` zone.

Abstract: A transistor chopper for controlling the power delivered to a DC load from a DC source includes two or more transistors connected in series between the DC source and the load and means for controlling the voltage across each transistor so that the transistor is subjected to only a fraction of the open circuit voltage developed by the DC source. Lower power transistors may therefore be used as switching elements in the chopper, and hence the overall cost of the system is reduced over prior choppers.

Abstract: A direct current electric motor marine propulsion system is provided with a pair of shunt wound direct current electric motors which are alternatively connected in a series/parallel circuit configuration. A forward biased diode between the motors in the series circuit, provides for smooth switching characteristics. Fine control of low speed operation is accomplished through the use of a chopper in series with the power source. A contactor connected across the diode provides for reverse current flow during regenerative braking.