FIRGELLI engineering guide
A linear actuator base model rarely tells the whole story. The suffix can define voltage, stroke, force, speed, feedback, cable, connector, duty cycle, IP rating or even an internal limit-switch option.
This guide explains how to read an actuator label and why a replacement search should use the complete part number, not just the product-family name.
Key Engineering Takeaways
- A base model can cover many strokes, forces and electrical options.
- Suffixes and option codes may change mechanical length, speed, feedback and controller compatibility.
- Do not force a stroke value onto a base model when the suffix is missing.
- Replacement matching should show ranges when only a product family is known.
- Use the cross-reference a replacement actuator when a label includes a manufacturer and exact part number.
Engineering Guide
1. Why actuator model numbers are easy to misread
Many actuator families use a core model name plus suffixes. The core name may identify the product family, but the suffix may identify the usable stroke, load rating, voltage, speed, feedback output and connector. Two actuators can share the same base model and still be mechanically or electrically different.
That matters when replacing an actuator. A 12 VDC, 6 inch stroke, 150 lbf actuator with no feedback is not the same as a 24 VDC, 12 inch stroke, Hall feedback version from the same family. The label must be read as a complete specification.
If the actuator is being replaced, start with the find a replacement actuator from label and measurements and record the full label before removing the old unit.
2. What suffixes usually encode
Common suffix fields include stroke, force, voltage, gear ratio, speed, feedback type, cable length, connector type, IP rating, brake option, clutch option and custom customer code. Manufacturers do not use one universal order-code structure, so the same position in the part number can mean different things across brands.
Treat every suffix as meaningful until proven otherwise. If the last two characters look minor, they may still define a feedback connector, limit-switch logic, mounting feature or regional variant.
For feedback terms, compare compare potentiometer and encoder feedback and review feedback options for linear actuators before connecting a replacement to an existing controller.
3. How to handle missing or partial model numbers
When a label is missing, damaged or only shows the family name, do not invent the missing stroke or voltage. Measure the actuator. Record retracted pin-to-pin length, extended pin-to-pin length, stroke, mounting hole diameter, clevis width, cable count and wire colors. Then compare against published family ranges.
A good replacement shortlist should say what is known, what is assumed and what still needs checking. Missing source data is not a match. It is a check item.
Use decide whether to repair or replace a linear actuator and understand actuator repair and replacement parts to decide whether the actuator can be identified well enough for replacement.
4. Actuator example: family number without stroke
If an actuator label shows only a family such as a high-level model series, the correct display is a stroke range for that family, not one forced stroke. The replacement process should compare FIRGELLI families and then let the user select the stroke after measuring the installed actuator.
After the family is identified, use browse FIRGELLI linear actuators to compare actuator ranges and available stroke options.
Specification Checks
| Check | What it means | Engineering note |
|---|---|---|
| Base model | Product family or platform. | Usually not enough for replacement. |
| Stroke code | Travel length, often in mm or inches. | Always confirm units and measure travel. |
| Force code | Dynamic load rating or force family. | Check whether static force is listed separately. |
| Voltage code | 12 VDC, 24 VDC or other supply. | Do not substitute voltage without changing the control system. |
| Feedback code | Potentiometer, Hall, optical, encoder or none. | Controller compatibility depends on this. |
Field Checklist
- Manufacturer name
- Complete model number including suffix
- Separate part number or customer code
- Voltage and current rating
- Stroke and force rating
- Speed or gear ratio
- Feedback type and wire count
- Connector type and cable length
- Ingress protection or IP rating
- Revision, date code or regional variant
Common Mistakes
| Mistake | Why it causes problems | Better practice |
|---|---|---|
| Using only the family name | The replacement is selected from the wrong configuration. | Use the complete suffix or display the family range only. |
| Mixing units | A metric stroke is treated as inches or an inch stroke as mm. | Show both units and compare in normalized units. |
| Ignoring feedback suffixes | A mechanically similar actuator cannot talk to the controller. | Match signal type, pinout and controller expectations. |
Frequently Asked Questions
What part of a linear actuator model number matters most?
The full part number matters. The base family, stroke, force, voltage, feedback and connector suffixes can all change whether a replacement fits.
Can I replace an actuator if I only know the base model?
Sometimes, but it should be treated as a family-level comparison. Measure stroke, retracted length, extended length, mounting holes and voltage before choosing a specific actuator.
Why do two actuators with the same model name have different strokes?
Many manufacturers use one family name for multiple stroke options. The stroke is often encoded in a suffix or separate option field.
How do I know whether a suffix means feedback?
Check the wiring count and product documentation. If there are extra signal wires, review review feedback options for linear actuators before ordering or connecting a controller.
Should replacement search tools show one actuator or a family?
If the exact configuration is known, a specific candidate is useful. If the source only identifies a family, the honest result is a comparable FIRGELLI family with available stroke ranges.
What if the label is missing?
Measure the actuator and record electrical behavior. The missing label means more checks are required; it does not mean the closest-looking actuator is confirmed compatible.
Can suffixes affect IP rating?
Yes. Cable, connector, seal and housing options can change ingress protection. Treat the IP rating as configuration-specific unless the manufacturer documents otherwise.
