Analog dynamic range, accuracy and number of bits

necessarily

cultural

Smarter than little Willie then.

;-)

the

necessarily

cultural

Pretty much true, but i have seen current as J. Not quite the same thing though, kind of a generalization for use with plasmas and Maxwell's laws.

?-)

They paid enough that they didn't have to watch their p's and q's properly.

?-)

handle

Two things:

The way the certification process works.

They want new features that are not possible by just instrumenting rotating disk types.

?-)

I'm not defining it. I'm telling you what the industry conventions are.

Sure, use sign-magnitiude if you like. It's somewhere in the computer history books.

You mean for values >1 and

That would have been current *density*. Not just current.

Jeroen Belleman

Where real power may be positive or negative and apparent power is always positive. Therefore PF can be negative.

One such case is where an induction motor becomes driven above synchronous speed by another motor. Measuring Irms and Vrms tells little about this condition whereas real power will be negative.

Define things any way that suits you. The utilities and the measurement community have conventions of their own.

If the voltage and current waveforms are known, that's the whole story. Sample, multiply, and integrate and you get true, signed power. You can then, if you like, map the waveforms into concepts like positive and negative power, and leading and lagging (or even negative) power factor, and get confused.

I designed a bunch of cogenerator remote control and metering boxes, for the now-defunct Microcogen Company. The idea was to burn natural gas in a piston engine, generate electricity, and get as much hot water as a water heater would have made, for restaurants and such. My controller did measure signed power and unsigned PF. It was an induction generator so the phase angle was never in doubt. The cogen system worked, but the economics weren't worth the hassle.

Burning gas to heat water is inefficient; there must be a better way. With fracking making gas cheap, it won't happen soon.

Except when people need it to have a sign, then they give it one. In other words, they use a different definition from yours.

Words don't matter as much as waveforms.

Larkin bloviates. ...Jim Thompson

Perhaps. How many utilities need to provide power factor correction for a capacitive (leading) load?

( Snipped bragging )

Maybe other engineers, such as myself, do not suffer from confusion as you do.

Only in the special case of sine waves. Ex. cos(100) is negative. This can happen if the load begins to drive the source.

Actually, isn't power factor defined as P/VA? P is average (integral V*I*dt), and VA is Vrms and Irms? It is what I used when dealing with the power factor of large SCR-controlled rectifier bridges.

be

Probably none, but once some correction has been kicked in, the resulting net PF and lead/lag status must be known to close a control loop. Caps are selectable in discrete steps, and synchronous PF correctors are continuously adjustable. You can't close a control loop very well if you don't know which direction to go.

Well, I have designed a lot of power metering and control gear. How about you?

I'm not confused about this stuff. In a power system, voltage and current waveforms have relative timing that matters. In some cases, we couldn't get the customers to agree on terminology (especially for electronic loads) so we just delivered the actual waveforms and let them decide what to call them.

When you design electronic power meters, by all means do it your way.

I've seen residential meters like that, a disk and electronics, no mechanical register.

I'd use lower case for the v(t) and i(t) but, yes, that's the general definition, good for any waveforms.