Abstract: The electric vehicle driven by a DC motor having a field winding. An electric resistance element can be switched into parallel circuit with the field winding to weaken the field and increase potential motor speed. A relay operates the switch, a Hall-effect switch responsive to motor rotation produces voltage pulses indicative of motor speed. A microcomputer counts pulses in a given time period to determine motor speed and compares the speed with that in the prior period to determine whether the motor speed is increasing or decreasing. The computer is programmed to operate the relay to close the switch as the motor speed increases above a first speed and to open the switch as motor speed subsequently decreases to a second speed lower than said first speed. The computer is programmed to respond to a third speed greater than the first speed to operate the relay to open said switch to prevent overspeed.

Abstract: A motor driven vehicle has a safety control preventing operation of the motor if the operator is not in the drivers seat to close a seat switch for a predetermined period of time. The motor includes an electric circuit which when complete enables motor operation and which prevents motor operation when the circuit is open. A microprocessor opens the circuit when the seat switch is open and is programmed to provide a predetermined time delay before opening the circuit to stop motor operation. The computer decrements the time delay whenever the seat switch is open. The computer includes means for testing to determine whether the time delay has been reduced to 0 at periodic intervals shorter than the predetermined time delay. The decremented time delay is restored to full value if the seat switch is closed during such testing before said time delay has been decremented to 0.

Abstract: A motor vehicle powered by a DC motor has a pedal which is depressed by the driver to increase speed by actuating a tapping switch which has two sets of moving contacts cooperating with stationary contacts to progressively connect with the motor batteries from one or the other end of a bank of series connected batteries. An alternate action relay connected between said motor and the switch determines which of the two sets is connected in circuit with the motor. The relay has two positions to alternately connect one or the other of the tapping switch contact sets in circuit with said motor. A main solenoid switch is connected in series with the relay and the tapping switch. When the pedal is depressed, a foot switch operated by the pedal is operative to close a circuit enabling energization of the alternate action relay and the main solenoid switch. A microprocessor controls operation of the relay and the main solenoid.