Abstract: An AC glow plug system is provided that includes a static converter for DC to AC conversion. Control techniques include varying the converter duty cycle according to glow plug temperature and other parameters such as engine air or coolant temperatures for smooth running as well as for prolonging glow plug life. Control is also varied according to fuel system characteristics and fuel composition.

Abstract: An apparatus is provided for precharging a filter capacitor to prevent damage to a set of contacts resulting from arcing across the contacts. Included is a coil, a set of contacts, and a battery, such that the contacts and filter capacitor are connected in series and the series connected combination is connected in parallel across the battery. Also included is a switch, and a microprocessor for producing a triggering signal responsive to the closure of the switch. A driving circuit receives the triggering signal and responsively produces a charging signal. A charging circuit receives the charging signal and responsively charges the filter capacitor. Thereafter, the microprocessor produces an energizing signal causing the coil to become energized and the contacts to responsively close. By precharging the filter capacitor before the closure of the contacts, the voltage potential across the contacts is reduced. Therefore, no damage occurs due to arcing across the contacts.

Abstract: Motor control systems having solid-state components are commonly used on industrial vehicles such as lift trucks. Such solid-state components are easily damaged by excessive transient voltages. The subject invention includes a power supply for supplying direct current to a motor circuit, wherein the direct current has a nominal direct current voltage value and as associated transient voltage component. A pulse control circuit supplies current pulses from the power supply to a motor. A sensing device controllably produces a fault signal in response to the amplitude and frequency of occurrence of the transient voltage component exceeding a predetermined maximum value. An override circuit receives the fault signal and responsively modifies the current pulses delivered from the power supply to the associated motor.

Abstract: Motor control circuits having solid-state switching elements are commonly used on industrial vehicles such as lift trucks. A short circuit condition in the motor circuit can cause catastrophic failure of the semiconductor switching element. The instant invention detects such a short circuit condition and modifies the motor control signals supplied by a chopper circuit to a switching element. The apparatus includes a trigger circuit for receiving the motor control signals and sensing a voltage across the motor produced in response to electrical power delivered from a power supply.

Abstract: Disclosed is a workpiece collet mountable in a lathe spindle provided with a master stem on which any one of a set of workpiece stops may be mounted and which stem includes a support readily assembled to the collet repeatedly in a predetermined position. The stops differ in length and/or radius to accommodate workpieces of different terminal configurations. This permits one stop to be substituted for another with assurance that its outer end will be spaced a predetermined distance from the adjacent end of the collet when the master stem is reassembled to the collet. Both ends of the master stem are similarly threaded and finished with stop surfaces permitting the stem to be inverted and used to mount a selected one of the set of stops.

Abstract: In the control of two or more electrical devices powered by a common battery and each actuated by a separate controlled rectifier chopper circuit, at least one of which is an SCR chopper circuit, under high stress conditions requiring both electrical devices to be repeatedly and rapidly turned on and off it has been found that control over the SCR chopper circuit can be lost due to inherent inductive effects which prevent the charging of the commutating capacitor of the SCR chopper to at least full open circuit battery voltage. This problem is met by inhibiting the occurrence of an "off" actuation control signal to the SCR chopper circuit for a given period of time before and a given period of time after an "on" actuation control signal to the other chopper circuit.

Abstract: A brush which presses against the commutator of a direct current machine has a groove in one side thereof into which a fixed probe partially extends. As the brush wears, movement thereof causes physical engagement of the probe with the end of the groove to complete a current path through the probe. Flow through the current path energizes and latches a warning device.