When electrical power is applied, current flow through the solenoid coil winding creates a magnetic field, which produces an attraction between the movable parts. In a linear solenoid the plunger moves, and in a rotary solenoid the shaft and armature plate rotate. In a linear solenoid the fully energized position is when the plunger is in contact with the core (stop), and in a rotary when it has completed its specified degree of rotation.      Removal of power from the solenoid allows the plunger or rotor to return to its de-energized or rest position. The return to rest position is typically aided by a return spring, gravity, or the load itself, depending on the application.
     If the product development engineer has the time, circuit knowledge and form factor flexibility, he can design around a “standard solenoid” using the trial and error approach. While this approach is generally cost effective, time to market and last minute design changes can negatively impact the cost savings benefits. Assistance from a solenoid applications engineer in the initial stages of product design will allow the development engineer to avoid common pitfalls and ensure greater product success.
     A modified standard solenoid can often provide a balance between unit costs and design flexibility. Solenoids in this category typically can have custom windings, lead lengths with connectors, or plungers that mate to the application. Experience demonstrates that form factor, circuit characteristics, and load/force variables, often drive design modifications as identified during alpha and beta test activities. What started out as a standard solenoid often evolves into a modified standard. Like the standard solenoid, assistance from a solenoid applications engineer will reduce “what if” design variables and related multiple iterations that invariably occur.
     Custom solenoids are typically driven by unique form factors, narrowly defined circuit characteristics, and/or high performance criteria as it pertains to unique application requirements. Through the use of FEA design tools including magnetic modeling and analysis, the time to market can be compressed significantly. Once again, applications engineering support is invaluable.
     Bicron has substantially broadened it's range of solenoid solutions through it's exclusive North American representation for solenoids manufactured by Shindengen Mechatronics Co., Ltd. of Japan. This includes its full lines of rotary, push-pull, tubular, open frame, magnetic latching and proportional designs. For example: Maximum force values now range up to 70 pounds; Proportional solenoids, ideally suited to hydraulic control applications, are now available; Designs similar to existing Bicron standards are now generally available with higher force ranges. For more information about Shindengen products click on: Rotary or Linear.