Actuator Classification Calculation Audit

Actuator Classification Calculation Audit

Ada re-derives this chapter’s own numbers step by step, at full precision

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Ada ADA · CALCULATION AUDIT

Actuator Classification Calculation Audit

A door controller can drive a relay strike, a solenoid bolt, or a motorized latch, and the same “open” command hides very different loads: the strike pulls 1.5 A at 12 V for 18 W, its 80 mA coil still needs a driver and flyback path, and a 0.5 A solenoid dissipates 6 W held but only about 1 W when pulsed 10 s every 60 s. A companion vent load of 1.2 N at a 35 mm arm sets a 0.105 N m target once a 2.5x margin is applied. This audit re-derives each figure and asks whether one software verb can quietly cross a torque, startup-current, switched-power, or thermal boundary, so the selection record must name the matching physical proof.

Companion to the chapter Choosing the Right Actuator — every number here comes from that chapter.

— torque, current, power, and heat, ~4 minutes

The mathematics checks whether the chapter's examples point to the same classification boundary. The physics reminder is that torque, startup current, contact power, and coil heat are different failure surfaces even when the software command looks identical.

See the relationship before changing it

The figure reads from left to right. The blue card is strike current. The middle card applies this page's rule. The green card is strike electrical power. Walk the arrows once: set the input, apply the rule, then read the result with its unit.

The retained audit below checks several chapter fixtures. This model keeps those stated values fixed and changes only strike current, so the numeric fixture does not switch without explanation.

Strike current changes strike electrical power An input card leads through the rule power = 12 V x strike current to the strike electrical power result. INPUT PAGE INPUT APPLY THE RULE predict calculate check units OUTPUT RESULT
Walk the arrows. Current turns the same twelve-volt command into a larger driver and thermal load.

Derive the baseline in four named moves

  1. 1

    Name the input. The chapter baseline is 1.5 A.

  2. 2

    Name the relationship. power = 12 V x strike current

  3. 3

    Substitute with units. 12 V x 1.5 A = 18.0 W

  4. 4

    Read the result. Keep the unit beside the value. Use it only inside the technical boundary on this page.

Predict, then change strike current

Try Predict the direction of power = 12 V x strike current. Test another strike current, then compare strike electrical power.

1.5 A
Chapter baseline
Strike electrical power

Observe Current turns the same twelve-volt command into a larger driver and thermal load. Reset strike current to 1.5 and compare strike electrical power.

Explain Current turns the same twelve-volt command into a larger driver and thermal load.

Check yourself

What should you do before trusting a moved-control result?
Answer: Predict its direction, apply the shown relationship, keep the units, and reset to the worked baseline.
What does this small model leave out?
Answer: Only strike current moves here. Field effects named in the technical boundary stay fixed.

Honesty note. This teaching model changes only strike current. It is not a field prediction.

The chapter's values

Use only the chapter values above: a 1.2 N vent load at a 35 mm arm, a 2.5x margin, a 12 V fan at 0.7 A running and 2.1 A startup, a 1.5 A door strike at 12 V, an 80 mA relay coil, and a 0.5 A solenoid pulsed for 10 s every 60 s.

torque = force x arm; power = voltage x current; average_power = duty x continuous_power

The worked checks

Check Arithmetic Classification Evidence
Vent torque 1.2 N x 0.035 m = 0.042 N m The vent is a positioned-motion problem, so torque and final-state evidence matter.
Margin target 0.042 N m x 2.5 = 0.105 N m The actuator family must clear the load with margin, not merely rotate in free air.
Fan running power 12 V x 0.7 A = 8.4 W A continuous-flow actuator needs a real power driver and process evidence.
Fan startup ratio 2.1 A / 0.7 A = 3.0 The startup case is three times the running current, so normal current alone is not a safe sizing record.
Door strike load 12 V x 1.5 A = 18 W The relay or driver switches a DC load; command acknowledgement does not prove the door moved or secured.
Relay coil boundary 12 V x 0.080 A = 0.96 W The coil is smaller than the strike load, but it still needs a transistor driver and flyback path.
Solenoid duty heat 12 V x 0.5 A = 6 W; 10 / 60 = 0.1667; 6 W x 0.1667 = 1.0 W The pulsed heat case is about one watt before enclosure effects; continuous hold is six watts.

Audit conclusion: actuator classification is quantitative evidence. The same software verb can cross a torque boundary, a startup-current boundary, a switched-power boundary, or a thermal boundary, so the selection record must name the physical proof that matches the family.

Every number above is taken from the chapter’s own examples and re-derived step by step.

TryUse Check audit to compare a 12 V coil, pulse duty, force, arm radius, and the resulting torque loads.
ObserveThe power and torque rows separate continuous holding heat from the pulse and surge demands of each 12 V actuator.
ExplainElectrical power is V times I, whereas rotary suitability follows force times radius; one Open command therefore cannot erase distinct load classes.
Technical boundaries. The comparison uses fixed DC voltage, current, pulse duty, force, radius, and margin. It does not model coil temperature, contact arcing, inrush waveform, driver loss, linkage friction, motion sensing, supply sag, or failure modes.
Audit result

The 12 V, 0.5 A solenoid is 6 W held and about 1 W at 10/60 duty; that does not prove the bolt moved.