Power is expressed in energy output per unit time While expression in a coherent unit is preferred, reference to older units may still be encountered.
Coherent Units
|
Units
|
System
|
Symbol
|
Watts
|
|
Watts (Joule per second)
|
SIU
|
W
|
1
|
|
erg per second
|
CGS
|
|
10^(-7)
|
|
foot poundal per second
|
ft-lb-s
|
|
0.042140
|
where:
• Watts = newton • meter / sec = m^2 • kg • s^(-3)
• erg/sec = dyne • cm / sec = cm^2 • g • s^(-3)
• ft pdl /sec = ft^2 • lb • s^(-3)
• kilowatt = 1kW = 1,000 W
Noncoherent Units
|
Units
|
Symbol
|
Watts
|
|
calorie per hour (International Steam Table)
|
cal (IT) / h
|
1.163 * 10^(-3)
|
|
British thermal unit per hour
|
Btu / h
|
0.293071
|
|
horsepower
|
hp
|
745.70
|
|
horsepower (metric)
|
ch, PS
|
735.49875
|
Implementation: Convert input units to watts, then from watts to the output units.
