Actuator Power Supply Sizing Calculator

Estimate the continuous current, peak current, and recommended DC supply power for one or more actuators from run current, starting current, simultaneous starts, supply voltage, and design margin. The result is a preliminary engineering estimate, not a product rating or safety approval.

Calculate supply current and watts

Enter the measured or assumed inputs in one unit system. The calculator converts to SI internally, evaluates the stated model, and displays the result in the selected unit system.

Margin-adjusted continuous current estimate --

Estimated simultaneous starting current --

Calculated supply current estimate --

Calculated supply power estimate --

Enter values inside the documented model domain.

Engineering visualizer

Schematic, not to scale. The drawing updates from the production calculation engine and labels the main outputs.

Calculator by FIRGELLI Automations.

Embed this calculator

When embedded on another page, the calculator shows only the working tool. FIRGELLI attribution, the visualizer, and the calculation-error report remain available.

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What these current and watt numbers mean

The supply current this tool reports is the larger of two things: running current times how many rams you have, with your margin folded in, or the pile of start current if several of them kick at once. The watt figure is just that current times the DC voltage you typed. If start current wins, you need a supply that can hold that peak for a second, not a mean-load brick that sags and brown-outs the motors.

This is not a force rating and it is not a SKU pick. A 20 A, 12 V estimate still dies on thin cable, a shared fuse, or a supply that cannot deliver the peak. Measure run and start current on the real load if you can. Then size the PSU and the wiring for the same number.

What This Calculator Calculates

What does actuator power supply sizing mean? This quantity describes one specific part of the actuator design problem. It should be read as a model output, not as a complete product selection rule.

How To Interpret The Results

How should I interpret the actuator power supply sizing result? A larger result means the checked effect is becoming more important and should be compared with product data, mounting limits, or the next design check. A smaller result does not prove the whole system is safe.

When Not To Use This Calculator

When should I not use the actuator power supply sizing model? Do not use this model when the inputs are unknown, the mechanism is outside the stated boundary, or the decision depends on manufacturer ratings, fatigue, shock, compliance, or regulated safety approval.

Engineering model and calculation details

Estimate the continuous current, peak current, and recommended DC supply power for one or more actuators from run current, starting current, simultaneous starts, supply voltage, and design margin.

The page separates the calculator result from product selection. It explains the inputs, limitations, interpretation, and next design checks so the result is not mistaken for a complete actuator rating.

Governing equations

Quantity	Equation	Model meaning
Margin-adjusted continuous current estimate	`I_cont = n I_run M`	Calculates margin-adjusted continuous current estimate for the stated simplified model.
Estimated simultaneous starting current	`I_peak = n_start I_start`	Calculates estimated simultaneous starting current for the stated simplified model.
Calculated supply current estimate	`I_supply = max(I_cont, I_peak)`	Calculates calculated supply current estimate for the stated simplified model.
Calculated supply power estimate	`P_supply = I_supply V`	Calculates calculated supply power estimate for the stated simplified model.

Variables and canonical units

Symbol	Variable	SI unit	Domain
`actuator_count`	Number of actuators	1	finite engineering value in the documented model domain
`run_current`	Run current per actuator	A	finite engineering value in the documented model domain
`start_current`	Start or peak current per actuator	A	finite engineering value in the documented model domain
`simultaneous_start_count`	Actuators starting at once	1	finite engineering value in the documented model domain
`system_voltage`	DC supply voltage	V	finite engineering value in the documented model domain
`margin_factor`	Design margin factor	1	finite engineering value in the documented model domain
`continuous_current`	Margin-adjusted continuous current estimate	A	finite result from valid inputs
`peak_current`	Estimated simultaneous starting current	A	finite result from valid inputs
`recommended_supply_current`	Calculated supply current estimate	A	finite result from valid inputs
`recommended_supply_power`	Calculated supply power estimate	W	finite result from valid inputs

Assumptions and boundary conditions

Inputs represent one consistent operating condition.
The model uses the simplified boundary stated on the page.
The model begins and ends at the user-defined actuator or mechanism boundary.

Limitations and omitted checks

The result depends on user-entered values and simplified boundary conditions.
The model does not replace FIRGELLI product data, installation review, endurance testing, or a qualified engineering review.
Shock, fatigue, misalignment, mounting strength, and controller behavior may govern before the calculated value.

Worked example

Two rams, 5 A run, 20 A start, both start, 12 V, margin 1.2. I_cont = 12 A, I_peak = 40 A, I_supply = 40 A, P = 480 W. The brick is sized for the start, not the cruise.

What this model evaluates

Mode or effect	Status	Disclosure
calculated quantity	evaluated	The named output is evaluated for the stated model.
manufacturer rating	not evaluated	The result is not a manufacturer product rating.
installation detail	not evaluated	Mounting, alignment, shock, fatigue, and environment require separate review.

Common mistakes

Treating a simplified estimate as a manufacturer rating.
Mixing units or entering values measured at a different operating point.
Ignoring mounting, alignment, shock, duty cycle, or controller limitations.
Failing to compare the result with the next logical FIRGELLI design check.

Engineering references

OpenStax. University Physics Volume 2 - Direct-Current Circuits. Rice University, 2016. Supports: Ohm-law and DC circuit relationships used for voltage drop and power loss.. Accessed 2026-07-28. Source.
National Institute of Standards and Technology. Ampere and Electrical Measurement Context. National Institute of Standards and Technology, Accessed 2026. Supports: Electrical unit consistency for current, voltage, resistance, and power relationships.. Accessed 2026-07-28. Source.
National Institute of Standards and Technology. NIST Guide to the SI. National Institute of Standards and Technology, Accessed 2026. Supports: SI unit definitions and unit-consistent engineering calculation display.. Accessed 2026-07-28. Source.

Author, validation, and review status

Author: Robbie Dickson

Author profile: Robbie Dickson prepares FIRGELLI actuator education and calculator content for product users and engineering teams.

Engineering model type: Actuator DC power-supply current and power sizing workflow

Validation: The production JavaScript engine is compared with a separately written Python oracle across known-answer, SI/imperial-equivalent, boundary, invalid-input, and randomized cases.

Questions about this calculator or found an error? Message our engineering team.

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Actuator Power Supply Sizing Calculator