Abstract: A method for determining the charge state of a battery in a motor vehicle includes steps of applying a measuring voltage to a coil, cyclically reversing the polarity of the measuring voltage if the absolute value of the secondary current flowing through the coil exceeds a predetermined threshold value, scanning the secondary current, reconstructing the curve of the secondary current based on the scanned secondary current values, and determining the charge state based on the curve of the secondary current values.

Abstract: When a short-circuited FET is identified as one of low-side FETs, maximum phase voltages of three phases are detected when a steering operation is performed by a driver, and the detected maximum phase voltages of the three phases are compared with one another to identify a short-circuit phase. On the other hand, when a short-circuited FET is identified as one of high-side FETs, minimum phase voltages of the three phases are detected when a steering operation is performed by the driver, and the detected minimum phase voltages of the three phases are compared with one another to identify a short-circuit phase.

Abstract: A method and apparatus for accurately and reliably positioning an actuator arm (12) is disclosed. The actuator arm (12) is driven by a conventional DC motor (38). The conductors which supply current to the motor (38) serve as primary windings (60) of a current transformer (58). The signal induced on secondary windings (62) of the transformer (58) responds to fluctuations in average current flowing in the motor (38). These fluctuations are amplified (64) and filtered (66) so that an AC burst (68) is produced in response to each commutation of the motor (38). The AC burst (68) triggers a one-shot timing circuit (72), which generates a pulse that remains active until the AC burst (68) has decayed. The pulse disappears prior to a subsequent commutation of the motor (38). Thus, one pulse is generated for each commutation of motor (38). A counter (76) is clocked by these pulses. The counter (76) increments when the motor (38) moves in one direction and decrements when the motor (38) moves in the opposing direction.

Abstract: This invention pertains to an electrical machine whose excitation is coordinated to the respective rpm in such a fashion that a desired characteristic of induced voltage or delivered output is produced. For that purpose at least one portion of the windings generating or controlling the working flux of the machine or a resistance wired in series before the machine is connected to a rectifier circuit, which is supplied, through a frequency-dependent impedance network, with an a.c. voltage of a frequency proportional to the machine rpm.

Abstract: A circuit provides an electrical output signal proportional to but electrically isolated from a current flowing in a power circuit, and more particularly, to the current supplied to the field or armature winding of a DC motor load which receives power from a rectifier circuit coupled to an AC power source. The circuit includes a transformer including at least two windings, a primary and a secondary, wound on a saturable core. The primary winding is coupled to the power circuit, whereas the secondary winding is coupled to an output circuit along with control circuit means which are adapted to keep the core out of saturation in response to a power current flowing in the primary winding which by itself is adapted to drive the core into saturation. Accordingly, the time the core is not in saturation an output current flows in the secondary winding, which is related to the primary current by the turns ratio of the transformer.

Abstract: Disclosed herein is a control for a direct current motor including a field weakening solenoid switch including a solenoid coil, which control includes an electronic switch connected in series with the coil for selectively connecting the coil to a source of direct current, and a device adapted for providing an electronic digital signal having a frequency proportional to motor speed.

Abstract: A field weakening circuit for an electric motor comprises a switching circuit the impedance of which is variable connected in parallel with a field winding of the motor. The switching circuit impedance is variable in dependence upon motor speed and current, either continuously or in a plurality of discrete steps, to control the current through the field winding.

Abstract: A speed control device for use in a battery-powered vehicle wherein a shunt field current in a compound electric motor for driving the vehicle having a reactor connected in series therewith can be selectively controlled by using a variable resistor included in the circuitry and operatively interconnected to an accelerator pedal so that the resistance to the shunt field current may be changed accordingly to the extent of stepping-down on the pedal by the operator. The speed control device also features that a part of the vehicle's body structure of a ferro-magnetic material is used in combination as a core of the reactor so as to form a complete magnetic circuit for the reactor.

Abstract: Disclosed herein is a control for a direct current motor including a field weakening solenoid switch including a solenoid coil, which control includes a switch connected in series with a coil for connecting and disconnecting the coil to a source of direct current, and a device responsive to motor speed for operating the switch.Also disclosed herein is an overspeed control for a direct current motor including a solenoid switch which controls energization of the direct current motor, which is biased open, and which includes a solenoid coil operable in response to energization thereof to close the switch, which overspeed control comprises a switch connected in series with the coil for selectively connecting the coil to a source of direct current, and a device responsive to motor speed for operating the switch.