network analyzer

[bergie]

any advice on a network analyzer? i,m thinking of buying one to do energy audits.
which ones do you guys use and where can i buy it in the cape. i would need one that can download to a p.c.

[AndyD]

I don't understand the connection between a network analyzer and energy auditing.

[bergie]

i want to leave it connected for a few days to read the kvar,power factor, and load profile,etc.then work out how to save power

[AndyD]

We just use a standard class1 meter, ip addressable with data logging facilities. ZAPλ 3AM+ Link. If you're in Cape Town they're available through ACDC or Electromechanica.

[bergie]

thanks andy,but the i think the zapa,s are'nt portable. i see theres a few portable analysers in the electromechanica catalogue,but a bit pricey.even the 5amp clamps are about R 8500

[AndyD]

Depends on your definition of portable, they're fairly compact, no bigger than a portable unit and they're easy to install in a metering cabinet or in a decent sized commercial DB. The 'portable' power analysers are horrifyingly expensive to do exactly the same data acquisition, plus they're mostly not ipaddressable so won't give real time remote monitoring, they're going to set you back R35K-60K instead of R6K for the Zap meter. Also if you're going to leave a R50K item lying around days on end at a customers premises you should budget for separate insurance as well.

For current clamps we just use split CT's (a set of 4 costs approx R4000.00) but you can also use the spring loaded hall effect clamps which are far more expensive. You can also use the flexible Rogowski type clamps, very quick and convenient but they're hellishly priced, you might pick up a set for USD1000.00 if you shop around.

[bergie]

thats good advice,thanks again. what size split CT,s do you use?

[AndyD]

I have a range of 5A CT's, sets of 100A, 300A, 500A & 1000A. You could probably get away with just a set of 100A and 500A to start with unless you're dealing with larger factory installations. The problem is that for example you get 300A CT's in 2 different diameters to accommodate 2 different busbar sizes. I just purchased the set with the larger form factor and made up some spacing bushes from casting resin to allow the CT's to fit the smaller busbar sizes also.

[murdock]

i use the 3000 amp flex clamps....they are the best...the fluke 435 comes standard with these clamps and you dont need a seperate power supply and you can setup the fluke what range you want internally...but they dont work on my metrel unit...i had to buy another set of 3000 amp flex clamps which have to be powered by an external source...and they have a 30/300/3000 selector problem is is you use batteries they dont las tlong so you have to connect an external power supply...

fluke have just ome out with the best flex clamp i have seen to date for...it is small enough to fit into all those tight spaces.

some free advice becareful of this energy/power quality industry....when i started doing it 6 years a go i thought it would be simple...6 years and R200 000 later i am still trying to understand the solutions...collecting the data using the fluke 435 is now as simple as using my fluke 289 but when you have to present solutions to the problem and energy saving tips etc it becomes a whole different ball game...and if you mess up it cost big time...an example a power factor correction unit installed incorrectly....we are busy with an investigation where a R100 000 PFC unit was installed less than a year later R60 000 worth of the components are no longer working...the agents will not replace the components because the installtion was incorrectly designed...the person who sold and installed the unit has suddenly vanished...

i am not saying dont go into it just becareful....it has also become like the generator bussiness when there was load shedding every man and his uncle is now an expert in this field...there is good money to be made if you know what you are doing...and the market will grow as the price of electricity climbs.

[bergie]

thanks murdock i will keep that in mind. i will start with the existing customers and see how it goes.

[AndyD]

What's your long-term plan Bergie? are you offering this as an occasional service to existing customers or are you looking to energy consumption monitoring as a full time endeavor?

[murdock]

something else to consider...the dangers involved in doing energy and power quality profiles...connecting 3000 amp flex clmaps onto a 2500 amp supply bussbars is a tricky bussiness...especially when the neutral bar is at the back anf there is only access from the front of the panel...due to the risks involved i am considering selling all my equipment and rather getting someone else to do the actuall on site profiles...as i mentioned i have been doing for 6 years already but when i sit back and think of some of the tricky conection i have done...man i need a another whiskey...especially if you see some of the explosion on youtube and now moving up th 33kv mv switchgear...i can see my life insurance going thru the roof....people say you should wear ppe...but taking the force of the explosion into account chances are you will be killed from the shear force...which is capable of blowing you thru a brick in some cases...depending on the fault level at that point.

[bergie]

i think will do it just for existing customers for now and see how it goes.(maybe hire the equipment ) the 1st audit i must do,the main supply is 400 amps and all the cables are accessible.

[AndyD]

Well good luck, I'm not sure where you'd hire this kind of equipment from. Maybe just borrow Murdock's fluke setup....what are friends for after all?

[murdock]

why dont you contact your local electromechanica...maybe they have also got spare recorders lying around like they do in durban...or depending on what you are doing maybe they can do the recording for you if you buy the equipment required for the project from them.

this is a big problem in the industry when you have to compete against the people who supply the equipment...imagine if all us contractors joined togeter and opened our own wholesaler bussiness and got the prices they did...we could become more competetive....mmm...yeah right we cant even agree a a living hourly without screwing each other.

you want friends get a dog...i have 3...nice thing is no matter how badly i treat them they are always happy to see me...or it could be because they want food