I picked up a wallplug measurement device kind of like a WattsUp. It appears to be an excess from China/Hongkong source, the "junk" shop had just this one piece. But I grabbed it because I've seen nothing like this sold locally (we don't charge for PF so nobody cares) and everything else from the net only seems to be designed for 115VAC.
Now naturally with items of such origins, the instructions and specifications can be vague/unclear. One section says it works from
57Hz to 63hz, one part says it won't work with anything outside of a 85~250VAC 60Hz area, yet the label on the actual unit says 50/60Hz.It appears to work on my local 230/50Hz, the frequency function shows
49.8Hz so it seems that at least the frequency measurement component isn't having a fit.But the question is therefore, if the device is actually designed only to work within 57~63hz but tolerates working at 50Hz, would it still be accurate or would the readings for PF or VA be off by say 20%?
If it would be inaccurate by a certain factor, how do I calculate the actual values of VA or PF from the displayed readings? TIA!