Solenoid current control
AssigneeChandler Evans Inc.
InventorBrian D. Phelan
Life of this patent
Estimating the term…
Abstract
The response time and power consumption of a solenoid-type actuator are minimized through exercising control over a transistor connected in series with the solenoid coil and a current source. Upon receipt of a command signal the series connected transistor is driven into saturation for a period of time commensurate with the current flow through the coil to rise to the level where a magnetic field of sufficient magnitude to pull in the solenoid plunger will be generated. The solenoid current is, once the solenoid armature moves, reduced to that level needed to maintain the field by controlling the transistor such that there is a constant voltage across the solenoid winding.
Claims11
A current control for a solenoid actuator, the actuator including a coil and a movable armature associated therewith, said control comprising:
- normally non-conductive controllable solid state switch means, said switch means being connected in series with the actuator coil and a current source;
- means responsive to the voltage across the actuator coil for generating a control signal;
- means responsive to input command signals and to said control signals for generating trigger pulses;
- timer means responsive to said trigger pulses for generating switch control pulses of a first polarity and a preselected duration, said switch control pulses being of sufficient magnitude to cause said switch means to change from the non-conductive state to a saturated state, the duration of said switch control pulses being commensurate with the time required for the current through the actuator coil to increase to a level which will generate a sufficiently strong field to impart motion to the actuator armature;
- means for applying said switch control pulses to said switch means;
- and
- means for applying control signals of the said first polarity generated by said means responsive to the voltage across the actuator coil to said switch means when an input command signal is present.
Dependencies are inferred from the claim text.