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.
"Current sensing tells you the motor is working harder. It does not tell you why. Good brackets, hard stops, and correct sizing protect the mechanism first — feedback just gives you a second line of defense."
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 current spikes treated as jams. Motor inrush can briefly exceed the stop threshold. Use a short delay (0.3–0.5s) before reacting.
- Friction baseline drifts. Cold weather, dry bearings, or a contaminated guide raise normal current. The warning threshold no longer reflects a real overload.
- Side loading skews the reading. Misaligned brackets add friction the controller cannot distinguish from a real load increase.
- Feedback reacts after the damage. Current sensing has a response delay. A sudden hard impact can bend the rod before the controller stops the motor.
- Voltage sag changes current. A weak battery or long wire run lowers motor current at the same mechanical load, hiding overloads.
How should you test load feedback before trusting it?
- Measure current at the hard part of travel. Record current at the start, middle, and end of stroke under real load — not just at the easy midpoint.
- Simulate a jam intentionally. Block the mechanism and confirm the controller stops within your delay window without damaging anything.
- Test cold and hot. Run the same cycle at the temperature extremes the actuator will see in service. Adjust thresholds if current shifts more than ~15%.
- Cycle with the real load and real brackets. A prototype that works once on the bench proves nothing. Run hundreds of cycles in the actual mounting.
- Verify the stop is mechanical first. Disconnect feedback and confirm hard stops, limit switches, and fuses still protect the system.
Where does load feedback matter most?
- RV slide-outs and hatches: Detect jams from debris, ice, or misalignment before the actuator strips a gear.
- Marine deck hatches and covers: Catch obstructions and salt-fouled tracks early, before bending the rod.
- Industrial automation: Overload protection on press tooling, gates, and clamps prevents tool damage on misfeeds.
- Smart furniture and lifts: Anti-pinch behavior when a hand or object gets caught under a moving panel.
- Medical and patient-handling equipment: Load feedback adds a redundant safety check on top of mechanical hard stops.
