| 词条 | Horsepower-hour |
| 释义 |
| image = | caption = | standard = | quantity = Energy | symbol = hp⋅h | symbol2 = | namedafter = | extralabel = | extradata = | units1 = SI units | inunits1 = 2.685 MJ | units2 = CGS units | inunits2 = {{val|2.685|e=13|u=erg}} | units3 = English Engineering Units | inunits3 = {{val|1.98|e=6|u=ft⋅lbf}} }} A horsepower-hour (hph or hp⋅h) is an outdated unit of energy, not used in the SI system of units. The unit represents an amount of work a horse is supposed capable of delivering during an hour (1 (one) horsepower integrated over a time interval of an hour). Based on differences in the definition of what constitutes the 'power of a horse', a horsepower-hour differs slightly from the German "Pferdestärkenstunde" (PSh): 1.014 PSh = 1 hph = 1,980,000 lbf⋅ft = 0.7457 kWh. 1 PSh = 0.73549875 kW⋅h = 2647.7955 kJ (exactly by definition) The horsepower-hour is still used in the railroad industry when sharing motive power (locomotives.) For example, if Railroad A borrows a 2,500 horsepower locomotive from Railroad B and operates it for twelve hours, Railroad A owes a debt of (2,500 hp × 12 h) = 30,000 hp⋅h. Railroad A may repay the debt by loaning Railroad B a 3,000 horsepower locomotive for ten hours.[1] References1. ^{{cite web|url=http://www.trains.com/trn/default.aspx?c%3Da%26id%3D4172 |title=Archived copy |accessdate=2009-05-25 |deadurl=yes |archiveurl=https://web.archive.org/web/20081204023343/http://www.trains.com/trn/default.aspx?c=a&id=4172 |archivedate=2008-12-04 |df= }} {{measurement-stub}} 2 : Imperial units|Units of energy |
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