"Robert Swinney" wrote in message
...
ATP sez:

"That will be a big surprise to electricians. It can and should be
measured,
using an analog meter or a digital meter that calculates the root mean
square. AC voltage is also cyclic, does that mean we shouldn't measure
it?"

Sorry, ATP if I went way over your head with that one. I referred to the
measurement of
instantaneous current, of course. Getchersef a good EE handbook and look
that one up, OK ?

Bob Swinney


Like a kid who can't answer an essay question, you continue to top post out
of context, irrelevant information that you obviously don't understand. The
OP, Don wants to figure out how much it costs to run a 25 HP compressor. He
has taken current readings. These current readings and the characteristics
of his three phase service are enough to approximate the cost of running the
compressor. Instantaneous current is completely irrelevant. Here is what you
wrote:

"The simple answer is No; it is not practical to measure current in the
individual phases. This
pulsating current cannot easily be measured. I was wrong to try to show
that the current was 1/3 of
rated load current. It can be seen, though, that Power in each phase must
be equal to 1/3 total
Power if the phases are balanced. Simple logic supports this."

It's over, Bob. As in past technical arguments that you have attempted here,
you just keep digging the hole deeper.