The wrong linear actuator doesn't just underperform — it fails. And failure in the wrong application means damaged  equipment, costly downtime, or in medical settings, patient safety risks. This step-by-step guide walks you through every  decision point so you can specify the right actuator with confidence.

Why Getting Actuator Selection Right Matters

Linear actuators look simple — a motor, a gearbox, a screw, a rod. But the range of specifications across available models is enormous: force ratings from 50N to 50,000N+, strokes from 50mm to 1,500mm, voltages from 5V to 72V, IP ratings from IP23 to IP68. Choosing without a systematic approach leads to:

• Underpowered actuators that stall or fail under load
• Oversized actuators that waste space and cost
• Wrong IP rating that corrodes in outdoor environments
• Wrong duty cycle that causes overheating and motor burnout
• Missing feedback that makes position control impossible

The following 7 steps cover every parameter you need to specify.

Step 1: Define Your Force Requirement

Force is the most critical specification. Get this wrong and nothing else matters.

What you need to know:

• The mass of the load the actuator must move (in kg)
• The mounting geometry (angle, lever arm lengths)
• Whether the actuator pushes, pulls, or both

Quick calculation (for vertical lifting):

𝐹 = 𝑚×𝑔× safety factorF = m × g × safety factor

Where:

𝑚m = load mass in kg

𝑔g = 9.81 m/s²

Safety factor = 1.5 (light duty) to 2.0 (standard) to 4.0 (medical/safety-critical)

Example: Lifting a 50kg load, standard application:

𝐹 = 50 ×9.81 × 2 = 981𝑁F = 50 × 9.81 × 2 = 981N → choose an actuator rated ≥ 1,000N

For angled or horizontal applications, the calculation changes — use our Engineering Force Calculator for accurate results.

Always verify:

• Dynamic force (while moving) — must exceed your calculated requirement
• Static force (holding) — must support the load without movement

Step 2: Determine Stroke Length

Stroke is how far the rod extends from its fully retracted position.

How to measure:

1.Define the two positions the actuator must move between (Point A = retracted end, Point B = extended end)

2.Measure the distance the actuator attachment point travels between A and B

3.Add 5–10mm tolerance margin

4.Verify that the actuator's retracted length fits within your mechanism's physical constraints

Common stroke ranges by application:

Step 3: Select the Right Voltage

Voltage selection is driven by your power supply or control system.

Rule: Match the actuator voltage to your existing power supply. Running a 12V actuator on 24V increases speed but causes overheating and reduces motor life significantly.

JDR actuators are available in 12V, 24V, and 48/72V configurations across all product series.

Step 4: Calculate Required Duty Cycle

Duty cycle determines how frequently you can operate the actuator without overheating.

Duty Cycle =On Time(seconds)/(On Time+Rest Time)×100%Duty Cycle

Example: Actuator runs for 8 seconds, rests for 72 seconds = 10% duty cycle

Standard actuators are typically rated at 10% duty cycle. Industrial applications requiring more frequent cycling need actuators rated at 20%, 25%, or higher.

Add a 50% safety margin to your calculated duty cycle. For the 10% example above, specify an actuator rated at 15% or  20% duty cycle.

Never select an actuator rated exactly at your calculated duty cycle. Temperature, aging seals, and voltage fluctuations all reduce effective thermal headroom.

See our complete duty cycle guide for detailed calculation examples.

Step 5: Choose the Right IP Rating for Your Environment

IP (Ingress Protection) rating, defined by IEC 60529, specifies protection against dust and liquids.

Quick decision guide:

IP66 is the recommended standard for all permanently outdoor linear actuators. The cost premium over IP54 (15–25%) is trivial compared to the cost of field replacement after premature corrosion failure.

Read the full IP rating guide for detailed breakdown of each rating level.

Step 6: Decide on Feedback Requirements

Feedback allows the control system to know where the actuator rod is at any moment. You need feedback if:

• Your application requires the actuator to stop at specific intermediate positions (not just full extend/retract)
• You're synchronizing two or more actuators to move together
• You're integrating the actuator into a PLC or microcontroller system with position control

Feedback options:

Recommendation: For any application requiring intermediate stops or multi-actuator synchronization, specify Hall effect sensor feedback. It's more reliable than potentiometers in vibration-prone environments and compatible with virtually all modern control systems.

Step 7: Match to an Application Category

Use this summary table to cross-reference your requirements with the right JDR series:

Common Selection Mistakes (and How to Avoid Them)

Mistake 1: Choosing by Force Only

Force is necessary but not sufficient. Many buyers select an actuator with the right force but wrong duty cycle, then wonder why the motor burns out after a week. Specify all parameters, not just force.

Mistake 2: Underestimating Stall Current

Actuator current draw at stall (when the load exceeds the motor's capability or the rod hits a hard stop) is typically 3–5× the running current. Size your power supply, wiring, fuses, and switches for stall current, not running current.

Mistake 3: Forgetting the Mounting Geometry

The actuator only produces its rated force along its axis. Off-axis loading (side forces, bending moments) rapidly degrades seals, bearings, and the rod itself. Design your mechanism so the actuator operates in pure compression or tension, with proper pivot mounts at both ends.

Mistake 4: Specifying IP Rating Without Checking Connectors

The actuator body may be IP66, but if the cable connector is standard (open-pin), water will enter through the connector. Specify IP66 connectors and cable glands to match the housing rating.

Mistake 5: Using a Ball Screw Actuator in Patient-Support Applications

Ball screw actuators are efficient and precise but are NOT self-locking. A patient-support application (hospital bed, stairlift) requires a trapezoidal lead screw actuator that holds position without power. Always verify self-locking capability in safety-critical applications.

Fast Selection Checklist

Use this checklist before finalizing any actuator specification:

• Required dynamic force calculated with ≥1.5× safety factor
• Stroke length measured with 5–10mm margin
• Voltage matched to power supply
• Duty cycle calculated and specified with 50% margin
• IP rating matched to environment (IP66 for all outdoor)
• Feedback type specified (Hall, potentiometer, or none)
• Mounting style confirmed (clevis-clevis, clevis-flange, etc.)
• Wire gauge and fusing sized for stall current
• Operating temperature range confirmed for climate
• Self-locking requirement checked (patient-support applications)

Frequently Asked Questions

Q: What is the most important specification when choosing a linear actuator?

A: Force is the critical baseline — an undersized actuator simply won't move the load. But duty cycle is the most commonly overlooked specification that causes real-world failures. After verifying force, always calculate duty cycle before finalizing your selection.

Q: How do I know if I need Hall effect feedback?

A: You need feedback if you need to stop the actuator at any position other than fully extended or fully retracted. If your application is simple open/close (extend fully, retract fully), the built-in limit switches are sufficient. If you need intermediate stops, synchronization, or PLC position control, specify Hall effect feedback.

Q: Can I use one actuator to replace a hydraulic cylinder of the same stroke?

A: Possibly, with caveats. First, verify the force requirement — hydraulic cylinders in industrial use often operate at forces of 20,000–50,000N, which is beyond standard electric actuators. Second, check the duty cycle — hydraulics typically handle continuous operation while electric actuators have rated duty cycles. For forces up to 10,000–15,000N, JDR industrial actuators are viable hydraulic replacements with significant maintenance and cleanliness advantages.

Q: My application is outside — do I really need IP66, or will IP54 do?

A: IP54 is splash-resistant, not rain-proof. Even "mild" outdoor conditions — overnight condensation, morning dew, annual rainfall — will cause internal corrosion in an IP54 actuator within 1–2 years. The replacement cost and installation labour will far exceed the price difference between IP54 and IP66 at the time of purchase. For any outdoor installation, specify IP66.

Summary: Your 7-Step Selection Framework

1.Force — calculate with safety factor, verify dynamic and static ratings

2.Stroke — measure required travel, add margin

3.Voltage — match to your power supply (12V, 24V, 48V)

4.Duty cycle — calculate, add 50% margin, verify for ambient temperature

5.IP rating — IP66 for outdoor, IP54 for protected indoor medical

6.Feedback — Hall effect for position control, none for simple open/close

7.Application match — cross-reference with product series selection table

Use JDR's Engineering Force Calculator to calculate force requirements, or browse our product series directly: Standard | Mini | Medical | Industrial | Lifting Column. Still unsure? Contact our engineering team — we'll help you specify the right  actuator for your application.