strange voltages

[ians]

UPS tests.

I connected the major tech MT250 to the UPs to get an idea of how long the batteries would last with a 50 watt lamp connected.

This is where it got interesting ... I got some really strange reading on the display... take out the good old fluke meter and check... voltage is not a problem - 230 VAC on the fluke display ... however the major tech unit has voltages ranging from 165 - 186 VAC ... checked live to neutral ...neutral to earth ...live to earth ... then i realised it was a modified sine wave UPS.

[GCE]

A true RMS meter should pick up the correct voltages and I see they advertise as True RMS
I would ask for my money back from Major Tech as it cannot be true rms -

[ians]

It is not worth the hassle... this is why i dont waste my money buying major tech ...unless it has a K in the model number.

[ians]

The MT 250 arrived back this week ...with a test report indicating there is no fault ... ok.

So flip open the laptop and open CVS datalogger software...
plug the cable into the MT 250 and the laptop...
go to instrument tab ... correct time (also a good habit to ge tinto when using datalogging equipment) ... update the date and time ...press ok...
back to instrument tab ...datalogger setup ... sample rate 1 second ... channel setup voltage ... manual ...test 7 ...setup ...
unplug the unit from the latop and take it to the voltage sensor and plug it in...
press and hold start/stop ... until rec appears on the display...
leave it for an hour ... press stop/start until the rec is off...
plug it back into the laptop go to instrument tab ... download data ...a tab "waiting for connection" ... "connected"...
click on download ... "logging..." appears on the screen ...a blue line fills the tab and then you wait .... and wait .... and wait ... and wait...

what should happen ... a graph should appear on the screen with all the info...
test 8
rec channel :voltage
sample rate: 1 s
start time
datano
mx min
with a graph below it

not so lucky

So i take the unt to another laptop and try the same thing ... same problem.

So I open an old file to view (before it started its journeys back to major tech repair centre) the files open no problem ... I view the content.

Tried everything ... even instrument tab ... previos measurments ... no luck ... import data to list ... nothing.

So i contact Major tech at 8 am this morning and leave my contact details with tier Durn branch and head office ... apparently everyone is on leave today ... so it looks like the piece crap will sit on my desk for another week ... its been months of return trips to the technical department so whats another couple weeks

Major tech ... your service is as bad if not worse than the MT products you sell.

https://www.major-tech.com/product/t...urrent-logger/

I should have spent the extra R6k and bought the K series unit.

https://www.major-tech.com/product/t...eakage-logger/

[AndyD]

The fast rise time of a squarer waveform might not be compatible with the input circuitry of the MT250, I doubt they'd outright lie about it being true RMS if it wasn't but never say never. I think you've just got to be aware of the limitations of any particular tester your using and the suitability of it for the particular test you're doing. I've seen a couple of occasions where people got a whack from or caused flash damage to lighting on dimmer circuits because of the high frequencies of the power waveform being misinterpreted by the tester they were using.

[ians]

Checked the unit on another computer ... works fine ... try both my computers again it works on downloads up to 6 hours ... longer recordings dont work.

After hours of frustrations ... I figued out that the problem is the driver ... apparently my computers have an updated driver (6.3) and the MT250 requires driver 5.3 ... a couple hours later I eventually got the driver to load on the netbook ... still cant get it to work on the laptop.

[ians]

I looked at the replacement value of the MT 250 (over R4k) ...i decided to send it to major tech workshop... lets wait and see what they say.

Its handy for those silly jobs where you just need to monitor the geyser load for example or as in my case battery life of a UPS or inverter.

I have considered purchasing an owl energy monitor ... not for accurate true RMS reading... but more logging and load profiles.

[GCE]

Hi
I recently (feb) bought a 3 phase logger and was tossing between the different makes and types.Thought I had thought of everything but once I got it and played discovered I had not.
If I had known covid was going to destroy cash flow I might have left it.

I decided to not get one with a screen .Find a screen is an attraction to theft vs a box lying in a panel. Tossed between single and 3 phase and decide to go 3 phase as the price did not seem that much more until I decided to buy and extra set of CT's to measure between 1 and 100 Amps - Most came standard with higher rated CT's
Ended up close to 60K
What I should have checked is that it is 4 quadrant because with solar and batteries feeding back to grid the readings are a challenge to separate. The extra CT's will be useful and I still would stick to something without a screen if you are going to leave it in a panel to measure over a period of time.

[ians]

The reason the driver will not load on my laptop ... it's windows 10.

Windows 10 has a security features which restricts access to certain exe files ... there are a few options to "switch off" the admin user acess control ... "This app has been blocked for your protection."

Just a waste of more of my time ... if i were the "technical person" at Major tech ... I would take the time to learn how to do it so that I could advise my customers how to resolve this issue

[AndyD]

I have a Chauvin Arnoux 3-phase data logger I paid over 60K for and that was a good few years ago but I rarely use it simply because of the high replacement price and being scared of it getting stolen when it's left on site to log. I also have a Zaptronix Lambda 4 quadrant meter and several sets of split CT's which make it capable of logging 3-phase supplies between 10Amps and 1000Amps, it costs about a tenth of the price of the Chauvin Arnoux but it's more than capable of high accuracy logging over a period of several weeks and I don't lose sleep when I leave it on site. As with you GCE, lessons learned the hard way.