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# Electrical Engineering/generator

Question
QUESTION: I need some up understanding this. When a generator is rate at lets say 10 kw at 10000 rpms does that mean that every second that the blades turn 166.66 (10000/60) to generate 10 kw every second or does that mean that at 10000 rpms your get 10 kw every minute.

ANSWER: If the manufacturer has tested the generator properly and quantified its ratings it means that the generator will, at a rotational speed of 10k rpm, produce 10KW of power.

But, watts, a power term where:

The electric power in watts produced by an electric current I consisting of a charge of Q coulombs every t seconds passing through an electric potential (voltage) difference of V is

P = IV =  (QV)/t

where
Q is electric charge in coulombs
t is time in seconds
I is electric current in amperes
V is electric potential or voltage in volts

Power can also be set to P = V*2 / R.

If the generator runs at this rated output for one full hour it means that the energy output is E = P * T = 10k * 1 hour = 10k kwatt hours.

Where energy: - That which does work or is capable of doing work. Electricity is energy that is measured in kilowatt hours.

If you are still confused, send me a follow up question and we can iterate on it one more time.

---------- FOLLOW-UP ----------

QUESTION: I'm confused, So if the generator has a 10k rpm and every second there are 10kw of power going out. than in one hour shouldn't you have 36000 kw of power in that hour.( 60 seconds time 60 minute in a hour time 10kw ). what i'm trying to figure out is the power output in minutes or seconds? So is the generator generating 10 kw every second or every minute becasue its a big difference.

Well, electrical power is just like mechanical power.  Take the engine in your automobile.  If you drive at a constant speed the engine must continually produce the power to keep the car going.  Same with the generator.  As it runs at full speed and loaded to maximum output it will keep producing that amount of power until the load is changed. If the load is disconnected, for example, and no current is passing to the load then the generator is still running and producing voltage but no current so no energy is being produced.

In your example of one hour power delivery it should be 36kw.hour of energy is outputted.

As the generator keeps running it continues to produce energy to the load. When the load is changed the amount of power and energy changes accordingly.  No load means no power being delivered. If the load is reduced to half then the power delivery is reduced accordingly.

By the way, 746 watts is equivalent to one horsepower.

Electrical Engineering

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#### cleggsan

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