Explicit unit definitions — sign preserved
Defined Power-Unit Converter
Convert a signed power value through watts using explicit SI, International Table heat-unit and horsepower definitions. Ambiguous “BTU”, “kcal” and “hp” labels are qualified.
W = J/shp(mech) ≠ hp(electric)BtuIT/hkcalIT/h
SI power
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Mechanical / electric horsepower
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Metric horsepower
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International Table heat-rate units
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Foot-pound-force rate
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Refrigeration ton (IT)
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The BIPM SI Brochure defines watt as J/s. Decimal SI prefixes are exact. NIST SP811 distinguishes International Table and thermochemical heat units;this converter uses only the explicitly labelled IT variants.
| Μονάδα | Watts per unit | Βάση |
|---|---|---|
| W | 1 | SI coherent derived unit |
| kW / MW | 1000 / 1000000 | Exact SI prefixes |
| hp(mech) | 745.69987158227022 | 550 international ft·lbf/s |
| hp(electric) | 746 | Exact defined unit |
| PS | 735.49875 | 75 kgf·m/s with gn=9.80665 m/s² |
| BtuIT/h | 0.293071070172222… | 1055.05585262 J / 3600 s |
| ft·lbf/s | 1.3558179483314004 | 0.3048 m × 4.4482216152605 N / s |
| kcalIT/h | 1.163 | 4186.8 J / 3600 s |
| TR(IT) | 3516.852842066666… | 12000 BtuIT/h |
Conversion only. Sign meaning, input measurement uncertainty, shaft/electrical/thermal boundaries, efficiency and time averaging are not inferred. Torque×rpm is a separate physical calculation `P=T·2πn/60`, not a power unit;the old rounded `/9549` pseudo-unit route was removed.
Πηγές
BIPM SI Brochure 9th edition,updated2026; NIST SP811 Appendix B.9; NIST conversion footnotes.
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