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The dimension of power is energy divided by time. In the International System of Units (SI), the unit of power is the watt (W), which is equal to one joule per second. Other common and traditional measures are horsepower (hp), comparing to the power of a horse; one mechanical horsepower equals about 745.7 watts.
Two common definitions used today are the imperial horsepower as in "hp" or "bhp" which is about 745.7 watts, and the metric horsepower as in "cv" or "PS" which is approximately 735.5 watts. The electric horsepower "hpE" is exactly 746 watts, while the boiler horsepower is 9809.5 or 9811 watts, depending on the exact year.
Power is the rate at which energy is generated or consumed and hence is measured in units (e.g. watts) that represent energy per unit time. For example, when a light bulb with a power rating of 100 W is turned on for one hour, the energy used is 100 watt hours (W·h), 0.1 kilowatt hour, or 360 kJ .
Engine power is the power that an engine can develop. It can be expressed in power units, most commonly kilowatt, pferdestärke (metric horsepower), or horsepower.In terms of internal combustion engines, the engine power usually describes the rated power, which is a power output that the engine can maintain over a long period of time according to a certain testing method, for example ISO 1585.
A typical turbocharged V8 diesel engine might have an engine power of 250 kW (340 hp) and a mass of 380 kg (840 lb), [1] giving it a power-to-weight ratio of 0.65 kW/kg (0.40 hp/lb). Examples of high power-to-weight ratios can often be found in turbines.
The motor may not reach this theoretical speed because there are non-linear mechanical losses. On the other hand, if the motor is driven as a generator, the no-load voltage between terminals is perfectly proportional to the RPM and true to the K v {\displaystyle K_{\text{v}}} of the motor/generator.
Correct use of the terminology may be confirmed by using the idea of fundamental units which are mass M, length L and time T, together with the idea of a dimension, i.e. power, of the fundamental unit, say L 1 for distance, and in a derived unit, say speed which is distance over time, with dimensions L 1 T −1 [167] The object of the jet ...
tech: approximate range of peak power output of typical automobiles (50-250 hp) 5–10 × 10 4 W tech: highest allowed ERP for an FM band radio station in the United States [27] 10 5: 1.67 × 10 5 W tech: power consumption of UNIVAC 1 computer 2.5–8 × 10 5 W tech: approximate range of power output of 'supercars' (300 to 1000 hp) 4.5 × 10 5 W