The total movement expected of the solenoid when electrical power is applied. It is also often defined as the air gap between moveable plunger and the fixed-pole piece in the de-energized condition. For greatest efficiency and smallest size, design for the shortest stroke possible.

SPOOL-LOCK® Solenoid

Electrohydraulic solenoids engineered to deliver performance and safety in harsh environments. These solenoids are designed to operate in extreme temperatures, sealed to withstand water ingression and submersion (up to IP-X9), resist an 800 lb maximum side load and pass a 96-hour salt spray (fog) corrosion test (ASTM B117).

Special Power

Applications which require different power levels than those available for standard, intermittent or pulse duty cycles. This covers applications at ambient temperature significantly above or below 76°F (25°C), or a desired current drain, below standard value, or a special duty cycle, or other design requirement affecting power.


A device comprised of a coil of wire, a housing and a moveable plunger (armature). When an electrical current is introduced, a magnetic field forms around the coil which draws the plunger in. A Solenoid essentially converts electrical energy into mechanical force.


Sleeving used on standard Solenoids to insulate the lead wires where they exit the Solenoid case is black Vinylite per Mil-I-631B, Type F, subform Ua, Grade C, Class 1, Category 1, and meets UL files E13565 and E-18459. Sleeving on high-temperature coils is Teflon for temperatures up to 200°C continuous, and will meet the requirements

Sleeve Bearing

The cylindrical bearing in the base of the solenoid which provides a guide for the shaft. Usually made from phosphor bronze, it can be made of other materials for different applications requiring longer life.

Service Cycle Life

Standard construction is nominally rated for 1,000,000 cycles. In actual service, cycle life exceeding this figure is constantly being experienced. Periodic cleaning and lubrication will help in extending life. Severe operating conditions—a heavy side load on the plunger, for example, may shorten cycle life. Since many factors other than the solenoid construction itself have this