Hello everybody,
I've read the page which describes how to make corrections on power factor (http://www.allaboutcircuits.com/vol_2/chpt_11/4.html) and there is something I don't fully understand.
This page says in the second paragraph that I can measure the true power with a wattmeter, while the apparent power can be calculated by multiplying the voltage and the current.
Based on my knowledge, the wattmeter has to wire coils. One is to measure the voltage accross the load, and a second to measure the current through it. The meters deflection comes from the combined effect of two coils inside the meter.
My question is, if the calculated and the measured power (apparent and true) values are created by the same quantities (ie: E and I) how can I get different results?
According to my impression they shall not be different.
If you have any idea, please share!
I've read the page which describes how to make corrections on power factor (http://www.allaboutcircuits.com/vol_2/chpt_11/4.html) and there is something I don't fully understand.
This page says in the second paragraph that I can measure the true power with a wattmeter, while the apparent power can be calculated by multiplying the voltage and the current.
Based on my knowledge, the wattmeter has to wire coils. One is to measure the voltage accross the load, and a second to measure the current through it. The meters deflection comes from the combined effect of two coils inside the meter.
My question is, if the calculated and the measured power (apparent and true) values are created by the same quantities (ie: E and I) how can I get different results?
According to my impression they shall not be different.
If you have any idea, please share!