PROPORTIONAL SOLENOID OPERATION
There are two critical design requirements that must be met for a proportional control solenoid. These are low hysterisis and a relatively flat force verses stroke curve at a given applied current. Both of these greatly affect the predictability, repeatability and the command response of the solenoid.
Low hysterisis is best accomplished through the use of bearings that reduce linear friction. A flat force verses stroke curve is achieved by proper design of the armature and pole pieces.
The advantage of the flat curve is that high predictability of position and force control of the solenoid is achieved. An example of a force curve for a proportional solenoid is shown below.
