Adrian Jadic wrote: > For unexplainable reasons there is a lot of inconsistency in rating (the > power of) equipment. > ... electrical motors are rated for output power ...
The above comment seemed to question why either input power or output power was needed for motors. Each is an important value to be known, for electrical motors, at least. The input power value is needed in order to make sure that the source of electricity (including capacity of the wires, fuses, etc.) is great enough to supply the power need to run the motor. The output power is needed in order to make sure that the motor is capable of providing the power need to do the job for which it is to be used. > I have no idea why would one need to have the input rating on a heater. The > nameplates also do not contain any efficiency on them. The input power to the heater is necessary in order to be sure the electrical circuits (especially fuses or circuit breakers) can safely carry the current necessary to supply the power needed. The output power for a heater tells us how fast it does its job of producing heat. But, for electical heaters, only one power rating is needed because the input and output are EXACTLY equal. ALL of the electrical energy supplied to the heater is converted 100% efficiently into heat. (Even if some energy is used to light an indicator light or to operate a thermostat, the energy supplied to those devices is ultimately also converted to heat, so there is no loss of energy.) Regards, Bill Hooper PS One COULD deliberately create an electrical heater that is less than 100% efficient. t would have to have a special feature that would cause some of the heat to be diverted from its intended destination, and would therefore truly be lost. But why would you want to do so? ============ Keep It Simple! Make It Metric! ============
