Abstract: Apparatus (10) is provided for controlling current through a motor (12), including a circuit (14) for generating motor speed command data, a circuit (26) for generating a control signal in response to a maximum value of current through the motor (12), a programmable data processor (72) for generating pulse trains in response to the command data, and a controllable supplying circuit (18) for coupling and decoupling power to the motor (12) in response to the pulse trains and for decoupling power to the motor (12) in response to the control signal independent of the pulse trains. By decoupling power from the motor (12) independent of the control produced by the data processor (72), the current limit is achieved even if the data processor (72) malfunctions, contrary to prior apparatus.

Abstract: Apparatus (10) for monitors and protects a plurality of contactor coils (14A-E) and coil drivers (16A-E) from damage owing to short circuits, and prevents the concurrent energization of more than a preselected number of the coils (14A-E). Included is a monitor (84) for sensing the total current flowing through the plurality of coils (14A-E) and supplying a variable current signal in response to a magnitude of the sensed total current, and a control (85) for receiving the variable current signal and controlling the energization of the coils (14A-E) in response to the magnitude of the current signal. By monitoring and controlling the energization of the plurality of coils (14A-E) damage due to excessive current flow through the coils (14A-E) is avoided and the number of concurrently energized coils (14A-E) is limited to the preselected number.

Abstract: Apparatus (10) for delivering electrical energy from a charging station (12) to a vehicle (14), for example, to charge a vehicle battery (16). The apparatus (10) includes vehicle and station bumpers (18,20) each associated with a respective wire coil (28,24), and forming respective flux path elements for the coils (28,24). Means (34) are provided for sensing the relative position of the first and second coils (24,28) and controllably delivering the electrical energy in response to the sensed position. Third and fourth coils (80,82) provide two-way communication between the station (12) and the vehicle (14), and blocking means (96) facilitates removal of the vehicle (14) from the station (12).

Abstract: An apparatus (10) is provided for controllably operating at least one solenoid coil (12) in a battery operated system. The mean voltage applied to the coil (12) is controlled in response to at least the battery voltage, facilitating the use of various battery voltages with a single voltage coil (12). The apparatus (10) is readily adapted for controlling multiple coils (12) and is digital in design.

Abstract: The invention pertains to a control circuit (10) for controlling the speed of a pair of motors (12,14), including a pair of switching elements (68,74) coupling power to the motors (12,14), a pair of controllable circuits (64,74) for driving the switching elements (68, 74), a circuit (36) for generating digital numbers representing the same command speed for each of the motors (12,14), a circuit (38) for generating digital numbers representing differential command speeds for the motors (12,14), and a data processor (56) for controlling the pair of controllable circuits (64,74) in response to the digital numbers. By utilizing digital and integrated circuit technology, prior, essentially linear, control apparatus, which are relatively unreliable, expensive and slow, need not be used.

Abstract: A voltage level monitoring and indicating apparatus (10) including a voltage-to-frequency converter (12), an input conditioning circuit (16) that shifts voltage signals received from different voltage sources to the same input level for the converter (12) which then produces a proportional output frequency signal, a microprocessor (40) which is software programmed to produce voltage level data in response to the output frequency signal from converter (12), and a display (42) which displays a range of numbers in response to the voltage level data. Prior apparatus are not state-of-the-art microprocessor based and require different designs when coupled to different voltage sources. The present invention is microprocessor based and has the same input conditioning circuit that can be coupled to different voltage sources for use principally to indicate voltage levels of batteries on electric fork lift trucks.

Abstract: Apparatus for determining the speed of an engine (10) and the phase shift between first and second shafts (16,19) rotatably driven by the engine (10). First and second fixed magnetic sensors (50,56) generate first and second signals (49,55) in response to movement of magnetically sensible members (47,53) through circular paths at speeds proportional to the speeds of the first and second shafts (16,19), respectively. Clock pulses from a fixed frequency clock (65) are counted to obtain a first count between successive first signals (49) and a second count between successive second and first signals (55,49). The first count is inverted to obtain information as to the instantaneous engine speed. The second count is divided by the first count to obtain information as to the instantaneous phase angle between the first and second shafts (16,19). Successive instantaneous information is averaged to cancel the effects of engine torsionals.

Abstract: A power supply circuit (20) having an inductive load (12), three power lines (A,B,C) for conducting current of a 3-phase AC source, an SCR network (24) of six SCRs (1-6) for coupling the current of the source between the power lines (A,B,C) and the load (12), a phase sensor (30) for generating a reference signal in response to one reference phase voltage (AB) of the source, and a trigger circuit (35) for triggering "on" the SCRs (1-6) at predetermined phase angles relative to the voltage (AB). The power supply circuit (20) overcomes constraints such as load inductance which limit the rate of current build-up or decay through the load (12) by gating "on" the SCRs (1-6) at the predetermined phase angles to maximize such current build-up or decay.

Abstract: An electronic engine control system (10) utilizing a digital microprocessor (30) for controlling the timing mechanism (13) and fuel pump rack limit (23) to set the engine timing of, and maximum allowable rate of fuel delivery to, an interval combustion engine (11) so that maximum engine performance is obtained with smoke and emissions limited to required EPA levels. A plurality of timing maps (61-64) are provided, for different modes of engine operation, each map having predetermined value timing control signals programmed therein corresponding to the optimal timing advance of a particular engine speed, or particulaoptimoptimal timing advance of a particular engine speed, or particular combination of engine speed and position of the fuel rack (21). A timing map selector (65) identifies the mode of engine operation and selects the appropriate timing map (61-64) to control the timing mechanism (13) by the particular programmed signal for the existing engine speed and fuel rack position.