Guys I bought a true power meter a while back and I used it for my first time he other day but I used it on a 3 phase motor.
My meter is not listed for use with 3ph equipment. I measured a 30hp motor with a nameplate rating of 43A(or 34 cannot recall there were two similar motors with slightly diff ratings). I got around 10kw on one of the two motors I measured, well a little under. This Measuremnt was from one phase to ground(voltage probes while clamp was on the phase) and from a phase to another with the voltage probes I got a out half(5kw or so).
Well my calculation from the name plate was a out double(around 20kw however this is a rough recollection so don't hold me to the sime math it is irrelevant to my question.
Oh and I forgot to mention the voltage was 480v(460 on the nameplate).
So, I know the basics to 3 phase such as li e voltage vs phase voltage but I don't understand everything.
Do I need a "3 phase power meter"to measure 3ph power? Because I do not know if there is such a meter and what the difference is? Does the meter clamps all 3 phases? And is it possible to calculate 3ph true power from using a single phase meter like mine and how do I do it? And why is the power about double from ground to a phase then it is from phase to phase?
After reading a little I picked up that 3ph motor already have a high power factor meaning that a simple V*A calculation should be close to a true power meter reading right? And if this is true then why do 3ph motors have a high power factor, I mean why?
Also, last question: I saw on the motor plates of these motors say PF 83.6. Is this not power factor because I know that power factor is always under 1. Is it possible it means .83 or so?
My meter is not listed for use with 3ph equipment. I measured a 30hp motor with a nameplate rating of 43A(or 34 cannot recall there were two similar motors with slightly diff ratings). I got around 10kw on one of the two motors I measured, well a little under. This Measuremnt was from one phase to ground(voltage probes while clamp was on the phase) and from a phase to another with the voltage probes I got a out half(5kw or so).
Well my calculation from the name plate was a out double(around 20kw however this is a rough recollection so don't hold me to the sime math it is irrelevant to my question.
Oh and I forgot to mention the voltage was 480v(460 on the nameplate).
So, I know the basics to 3 phase such as li e voltage vs phase voltage but I don't understand everything.
Do I need a "3 phase power meter"to measure 3ph power? Because I do not know if there is such a meter and what the difference is? Does the meter clamps all 3 phases? And is it possible to calculate 3ph true power from using a single phase meter like mine and how do I do it? And why is the power about double from ground to a phase then it is from phase to phase?
After reading a little I picked up that 3ph motor already have a high power factor meaning that a simple V*A calculation should be close to a true power meter reading right? And if this is true then why do 3ph motors have a high power factor, I mean why?
Also, last question: I saw on the motor plates of these motors say PF 83.6. Is this not power factor because I know that power factor is always under 1. Is it possible it means .83 or so?