Scope meters/power quality analyzers. maybe even PC based.

[fastline]

We have been kind of throwing around either getting a hand held or PC based scope. We are now realizing that having power quality analysis would be a HUGE thing for us for our industrial power issues. We would not use this in a professional setting so the best of the best is not a huge concern but do want decent quality.

Getting power quality requires analysis of the current and load compared to the voltage sine over time to determine the kw, var, thd, pf, etc. We looked at the Fluke 43B but they only have 2 channels and we would really like to have 3-4 channels. I think most digital scopes would cover our speed requirements.

So, does anyone know of some PC based packages for this type of catch all solution? Are there other hand helds other than Fluke that can compile all this data? The PC is enticing in that it should be cheaper to purchase and probably more modular, bigger screen, software updates might even be free, etc. I just hate to spend extra money on a processor, display, etc that we already have in a PC...

Open to discuss differences and advantages/disadvantages.

 

[crutschow]

I would think that if the PC is readily available and you are not concerned about portability, then the PC approach would give you the most bang for the buck, especially if you want to do a lot of analysis of the waveforms. The primary reason for using a regular oscilloscope as compared to a PC is that it's an all-in-one unit and easy to move.

I would look for a digitizing unit for the PC that meets your frequency and number of channels requirements. A Google search of "PC oscilloscopes" gave many hits, but I'm not familiar enough with them to give specific recommendations.

 

[Reloadron]

Personally I think you need to make a choice. A scope be it PC based or portable or whatever is just that, it is a scope. A power analyzer on the other hand is just that, a device designed and built to measure and analyze power. The latter will look at and record power harmonics, transients, sags as well as other power related features, many of which a scope will not measure well and record for extended time periods. The Fluke 43B is a very nice unit and carries a price tag around $2,900 give or take. It is also a single channel, single phase device. It offers 2 memory selectable parameters for like a few weeks, but is a single channel single phase device. Additionally it will not measure 3 phase power. You can measure 3 phase power quality going from phase to phase but not three phases at the same time. That also assumes balanced phases and loads.

Anyway, and just my take as I may be off base but I don't think you will find a scope that will measure well what a good analyzer will measure. Additionally if you plan to measure 3 phase power and view all three phases at the same time you will need the scope channels to be differential input w/ isolated grounds or buy three high voltage differential type active probes. Probes like that can run upwards of $1,000 each for decent Tektronix High Voltage Differential probes. Additionally they need powered from the host scope or external power source. You may want to consider that with a scope and measuring 3 phase power.

Just My Take
Ron

 

[fastline]

Thanks for the replies guys. We do need a certain level of portability and were planning to use the laptop for this. This would be the most portability we would need and the majority of scope functions would be used on a bench.

I am not opposed to 2 separate setups but the thing I really want to look at is the relationship of current and voltage or PF. Obviously any power quality meter will have to somewhat compare these wave patterns to even calculate the kw, pf, var, etc so it would seem an scope system capable of using an inductive hoop for a channel could apply some calcs for PQ stuff.

Obviously a simpler hand held clamp meter style PQ meter will give me the numbers I might be looking for but things like a SMPS will usually have a very unusual current graph with harmonics and and I would like to further look at the comparison to voltage. I guess all I am saying is I think I might be looking for a scope with PQ add ons rather than the other way around since all you really need to do all the PQ calcs in that graph from the current. basically another inductive clamp input.

Are there companies that specialize solely in PC based solutions? I did stumble upon this. PicoScope 3205 Virtual Oscilloscope Review by Everyday Practical Electronics It seemed to have decent specs but obviously not really covering my needs (wants) either. I guess this is one question worth asking - do I need 2 meters or one? Is a 4ch, pc based scope going to be super pricey? Most of my needs would be pretty slow but with a lot of samples in a short amount of time with fast triggering to look at square wave reponses. I would need to determine the pulse width and frequency basically.

 

[Mosaic]

Have a look at the Bitscopes.

BITSCOPE = PC OSCILLOSCOPES AND ANALYZERS