Load feedback is not the same thing as position feedback. Position feedback tells you where the actuator is. Load feedback tells you something about force, current, impact, or overload. Mix those up and you can build a controller that moves accurately while still crushing the mechanism.
Failure modes matter more than ideal specs. A motion system that works at rated current on the bench can still jam, side-load, or stall in the field. Design the feedback strategy around what can go wrong, not around the catalog number.
"Load feedback is information, not protection. I've seen designers trust a current threshold to save a mechanism that should have had a hard stop in the first place. Size the actuator correctly, guide the load, put real end stops in, and then use feedback to catch the conditions you couldn't design out." — Robbie Dickson, Founder and Chief Engineer of FIRGELLI Automations
What is load feedback?
Load feedback gives the control system information about the force or resistance the actuator sees. It can come from a true force sensor, current sensing, or built-in overload protection.
What is the simple explanation?
Position feedback answers “where is it?” Load feedback answers “how hard is it pushing?” Those are different questions.
Use the simple relationship below as a first-pass current-sensing warning estimate.
Load warning current = normal current × warning multiplier
What should the calculator inputs be?
Use this as a first-pass sizing tool. Then confirm the final choice against the actual FIRGELLI product page, the wiring diagram, and your real mounting geometry.
How do you use this calculator?
- Enter the real project values, not guesses from a different mechanism.
- Use measured current, load, stroke, voltage, or signal values where you can.
- Add margin for real brackets, wiring, friction, and installation conditions.
- Click Calculate to see your result.
Which signal should you trust?
Trust the signal only for what it measures. Current sensing gives a useful overload trend, but it does not know linkage angle, friction, side load, or exact force at the workpiece.
If the project can injure someone or damage expensive hardware, use hard stops, guarding, limit switches, and mechanical design first. Feedback supports safety. It does not replace it.
What is a simple example?
An actuator normally draws 6A while moving a lid. A warning multiplier of 1.5 gives 9A. A stop multiplier of 2 gives 12A.
If current stays above 12A for 0.5 seconds after startup, treat it as a jam or overload condition and stop the motion.
Recommended FIRGELLI setup
Which FIRGELLI products fit this job?
Choose the actuator first from load, stroke, speed, and environment. Then choose what feedback signal you actually need.
Bullet Series 23 Cal. Actuator
Use this family where compact motion and built-in stop behavior matter. Always confirm the exact model page for current force and stroke options.
View Bullet 23 Cal. Actuators
Utility Linear Actuator
Use this for compact, quiet projects where worm gear behavior and built-in feedback options can help the control strategy.
View Utility Actuators
Industrial Linear Actuator
Use Industrial actuators for heavier or harsher applications where rugged construction and optional feedback wiring matter.
View Industrial ActuatorsFor controller features around feedback-based movement, use the FCB-2 actuator controller.
What usually goes wrong with load feedback?
- Startup spike false trips. Inrush current at motion start can exceed the warning threshold, causing nuisance faults if no delay is set.
- Missed jams at low load. A mechanism that normally draws 6A may bind at 8A — well below a 12A stop threshold — and grind without ever triggering protection.
- Side load damage invisible to current sensing. Bent mounting brackets create off-axis load that destroys actuator internals while current stays near normal.
- Cold-weather and voltage sag drift. Current draw shifts with temperature and supply voltage, so a threshold tuned in summer may false-trip in winter.
- Wear-driven drift. Friction and gear wear gradually raise normal current over months, eroding the margin between normal and warning thresholds.
How should you test load feedback before trusting it?
- Measure normal current with the real load and real linkage geometry — not on a bare actuator on the bench.
- Run the cycle when the motor is cold and again when it is warm; record both currents and choose thresholds that work for the worst case.
- Deliberately stall the actuator against a fixed stop and confirm the stop multiplier and delay actually halt motion before damage.
- Cycle the mechanism repeatedly under real load — at least dozens of cycles — to see whether current drifts as the gearing seats in.
- Test at the lowest and highest supply voltage the system will see in the field. Current scales with voltage, so a threshold tuned at 12.6V may behave differently at 11.5V.
Where does load feedback matter most?
Marine hatches and RV slide-outs benefit from overload protection because environmental load (wind, ice, debris) can change without warning. Industrial covers and access panels use current sensing to detect jams from misaligned parts. Robotics grippers and pinch-point mechanisms need feedback to avoid crushing whatever they grab. Smart furniture (lift desks, hidden TV lifts) uses overload thresholds as a soft anti-collision system. In each case, feedback handles the unpredictable; mechanical design handles the predictable.
Industry tags: industrial, marine, rv, robotics, smart-furniture, automotive
