FIRGELLI engineering guide
Long actuator cables create two separate problems. The motor may see less voltage under load, and the feedback signal may become noisier or less reliable by the time it reaches the controller.
This guide explains the practical checks for 12 VDC and 24 VDC actuator systems, especially when motor power and feedback wiring share a long machine route.
Key Engineering Takeaways
- Voltage drop must be calculated using the round-trip conductor length.
- Startup and stall current create the worst voltage-drop cases.
- Low motor voltage can reduce speed and available force.
- Feedback wiring should be protected from motor noise and loose grounds.
- Potentiometer, Hall and optical feedback fail in different ways when wiring is poor.
- Start with estimate actuator cable voltage drop and loaded speed and calculate wire size and voltage drop before installing long actuator cables.
Engineering Guide
1. Voltage drop is a motor-performance problem
A 12 VDC actuator does not care what the power supply reads if the actuator only receives 10.5 VDC while moving under load. The motor sees the voltage at its terminals. Long wire, small gauge, weak connectors and high current all reduce that voltage.
Calculate voltage drop over the complete current path: out to the actuator and back. The higher the current and the longer the cable, the more important conductor size becomes.
Use use the linear actuator voltage drop calculator, calculate cable size from current and voltage drop and size a power supply for a linear actuator together when the actuator is far from the battery or supply.
2. Feedback accuracy depends on clean signals
Potentiometer feedback is analog. It can be affected by supply variation, ground noise and long cable runs. Hall and optical feedback are pulse based. They can be affected by missed pulses, noise pickup, poor grounding or controller input limitations.
A shielded or twisted feedback pair can help in noisy machines, but wiring practice matters too. Keep motor wires and feedback wires separated where practical. Do not run feedback beside high-current switching cables without considering noise.
Use estimate linear actuator feedback drift and compare Hall effect and optical encoder feedback when a position problem appears only after installation.
3. Separating power and signal wiring
Some actuators bring power and signal out in one cable. Others separate motor power and feedback. Separate routing makes it easier to keep high-current motor conductors away from low-level signals, but it also creates more connector and strain-relief points to manage.
For moving equipment, cable flex and connector retention matter as much as electrical theory. A perfect wiring diagram fails if vibration pulls on a connector or the cable rubs through on a bracket.
Review choose actuator connectors and wiring connections and wire a 12 VDC linear actuator safely before cutting and extending actuator leads.
4. Actuator example: feedback actuator on a long machine frame
A feedback actuator mounted 20 ft from the controller may run acceptably when unloaded but lose position accuracy under load. The motor current causes voltage drop, the motor wires radiate switching noise, and the feedback return may shift relative to the controller input. The fix is usually a combination of larger power conductors, cleaner routing, better grounding and verified controller input settings.
Where feedback is central to the application, compare products in the compare FIRGELLI feedback actuators and validate the installed cable length before production.
Specification Checks
| Check | What it means | Engineering note |
|---|---|---|
| Cable length | Physical distance between supply/controller and actuator. | Use round-trip length for voltage drop. |
| Motor current | Running, startup and stall current. | Worst-case drop occurs at high current. |
| Feedback type | Potentiometer, Hall, optical or encoder. | Each signal has different noise sensitivity. |
| Grounding | Return path used by motor and feedback. | Shared grounds can shift signal reference. |
| Controller input | Voltage, pulse count, analog input or digital input. | Must match the feedback device. |
Field Checklist
- One-way cable length and round-trip conductor length
- Actuator running, startup and stall current
- Allowed voltage drop at worst load
- Wire gauge and connector current rating
- Ground path and return conductor quality
- Feedback type and signal voltage
- Controller input type and pulse limits
- Power and feedback separation
- Shielding or twisted pair where needed
- Voltage measured at actuator under load
Common Mistakes
| Mistake | Why it causes problems | Better practice |
|---|---|---|
| Using one-way length in voltage-drop math | The wire looks half as long electrically. | Calculate the complete out-and-back path. |
| Extending feedback without checking noise | Position errors appear only on the machine. | Separate signal wiring and verify with the controller. |
| Trusting no-load speed | The actuator slows under load because voltage drops. | Measure speed and voltage under the real load. |
Frequently Asked Questions
How far can I run cable to a 12V linear actuator?
There is no fixed distance. It depends on current, wire gauge, allowed voltage drop and connectors. Calculate the round-trip voltage drop and measure voltage at the actuator under load.
Why does my actuator move slower with a long cable?
The actuator may be receiving less voltage while loaded. DC motor speed and available torque are affected by voltage at the motor, not just voltage at the power supply.
Can long cable runs affect Hall feedback?
Yes. Hall feedback uses pulses, and poor routing, noise, weak grounding or controller input limits can cause missed or false counts.
Is potentiometer feedback better for long wires?
Not automatically. Potentiometer feedback is analog and can be affected by ground shift and noise. The best choice depends on the controller and wiring environment.
Should motor wires and feedback wires be separated?
Where practical, yes. Separating high-current motor wiring from low-level feedback wiring reduces the chance of noise coupling into the position signal.
What calculator should I use for actuator wire size?
Use the estimate actuator cable voltage drop and loaded speed for actuator-specific voltage drop and calculate wire size and voltage drop for general AWG and mm2 cable sizing.
What should I measure if feedback position drifts?
Measure voltage under load, inspect grounds and connectors, check signal routing, verify controller input settings and compare physical stroke against reported position.
