Every solenoid selection resolves to four numbers: coil voltage, required stroke, required force at that stroke, and duty cycle. Everything else — body style, insulation class, mounting, connector — follows from those four and from the space they have to fit into. This page runs the selection in that order and links the article that goes deeper at each step.
What Are the Four Numbers That Determine Every Selection?
| Number | What It Determines | Mistakes to Avoid |
|---|---|---|
| Coil Voltage | Coil design, inrush current behavior, drive circuitry | Specifying the nominal power supply voltage instead of the voltage measured at the coil terminals under load |
| Stroke | Body style and frame series | Specifying the total mechanism stroke instead of the specific travel the plunger must generate |
| Force at That Stroke | Frame size and coil volume | Comparing catalog forces—which are specified at zero or near-zero air gap (to understand why the difference is so vast, see How to Read Force-Stroke Curves) |
| Duty Cycle | Thermal survival, insulation class | Estimating a percentage instead of providing the actual on-time and off-time |
If any of these four items are still uncertain, simply describe the mechanism directly—guessing and plugging in values will skew the entire derivation process. A guessed number quietly anchors the whole selection, and the errors will only surface on the physical machine.
How to Navigate the 4-Step Selection Process?
Step 1 — Accurately Interpreting the Specifications
Most selection errors stem from misreading data rather than faulty engineering judgment. In addition to numerical values, datasheets specify test conditions—and these conditions are often the hardest part to transfer across different manufacturers.
How to Read a Solenoid Datasheet: 7 Critical Parameters and Common Misinterpretation Traps breaks down the seven most critical parameters and their most frequent misinterpretation pitfalls. Complete Guide to Solenoid Principles & Applications: From Magnetic Circuit Design to Selection in Six Major Industrial Scenarios explains how magnetic circuit design generates the force-stroke curve you are reading. If solenoids are a completely new domain for you, What Popular Solenoid Science Videos Leave Out: Understand Working Principles and Industrial Selection Keys in 60 Seconds is your quickest starting point.
Step 2 — Narrowing Down to the Right Series
Five primary frame configurations cover nearly all industrial requirements, each featuring characteristic force-stroke behavior. Narrowing down to the appropriate series before comparing specific part numbers saves the most time.
Open Frame Solenoid Guide: Force-Stroke Curves and Duty Cycle explains the force-stroke curves and duty cycles of open-frame designs. Latching Solenoid Design Guide: Pulse Actuation and Zero-Power Holding covers bistable products that maintain position without continuous power. Why Do Latching Solenoids Save Energy? Low-Power Selection Guide for Continuously Energized Devices examines the same series from an energy budget rather than a mechanical standpoint. AC Laminated Solenoid Analysis: Inrush Current, Noise, and Specification Guide explains inrush current, acoustic noise, and how to properly specify AC laminated models. For side-by-side comparisons, use the Selection & Comparison Hub; to browse the complete catalog, consult the Product Family Overview.
Step 3 — Mapping Application Constraints
What turns a “theoretically correct selection” into a “field failure” are often the constraints absent from datasheets: cleanroom outgassing, washdown cleaning, explosive environments, vibration, or fail-safe directional requirements.
Semiconductor Equipment Solenoid Selection Guide: 4 Critical Constraints Never Listed on Datasheets covers four constraints unique to semiconductor equipment. Solenoid Selection for Smart Lock Brands: Understanding Design Differences Between Door and Automotive Locks explains the design distinctions smart lock brands genuinely need to consider. Automotive Solenoid Procurement Guide: Selection Metrics and Supplier Evaluation for Central Locks, Transmissions, and Oil Pumps outlines selection metrics and supplier evaluations for automotive applications. Explosion-Proof Solenoid Valve Selection Guide: Safety Specification Requirements for Chemical, Energy, and Hazardous Environments covers safety specifications in explosive environments. If your control element is a valve rather than a bare actuator, the Solenoid Valve Selection Tool: Quickly Filter Valve Types by Flow Rate, Pressure, and Media helps quickly filter valve models by flow, while Solenoid Valve Principles & Selection Pitfalls: 15 Critical Fluid Control Q&As for Junior Engineers addresses the fifteen most common myths we encounter. Laboratory and analytical instruments carry their own set of constraints—heat, vibration, stray magnetic fields, and particulate generation; see How to Select Solenoids for Laboratory Automation.
Step 4 — Procurement, Cost, and Supplier Evaluation
The final step is not purely technical. It dictates what happens if a specification turns out to be wrong later on, and how much it will cost to make a change at that stage.
The Truth About Solenoid Minimum Order Quantities (MOQ): Why MOQ Isn’t Absolute and How to Negotiate Flexible Terms explains why minimum order quantities are not rigid absolutes. Solenoid Procurement Cost Optimization: How Modular Specifications Reduce Development and Mass Production Costs explores where development and mass production costs truly originate. How to Choose a Taiwan Solenoid Manufacturer? 10 Essential Audit Criteria for OEM/ODM Procurement provides ten audit criteria for evaluating OEM partners. Out of Space for SMC or Festo Pneumatics? Custom Solenoid Replacement Evaluation Guide for High-Precision Equipment addresses scenarios where standard pneumatic components simply cannot fit.
How Shih Shin Technology Supports Selection
The cost of a selection error is not in the component itself, but in having to redesign the mechanism. That is why we prefer to ask for four numbers before providing a quote: stroke, force at that stroke, coil voltage, and duty cycle in seconds. With these four numbers in hand, model selection usually hits the mark on the first attempt; missing just one leaves the answer to guesswork.
With These Four Numbers in Hand, Selection Is Usually Right the First Time
This page breaks selection down into four steps, but the answer really comes down to four numbers: coil voltage, stroke, force at that stroke, and duty cycle measured in seconds. With all four, selection is mostly right the first time; miss one, and the rest is guesswork—and the cost of guessing wrong rarely lies in the part itself, but in having to redesign the mechanism.
The missing item is usually not unattainable, but simply hasn’t been measured yet—especially the duty cycle. Rather than filling in a percentage from a spec sheet, it is far better to directly record how many seconds it is energized and how many seconds it rests during the machine’s busiest cycle.
Send these four parameters along with ambient temperature and available installation space to info@solenoids.com.tw or fill out our RFQ form. We usually reply within 24 to 48 hours on business days, pointing out matching series or models while clearly identifying any parameters that cannot yet be confirmed from the available information. If you already have an existing part and are looking for a replacement, our part number cross-reference table is a faster starting point.