Clamp Meters New & Old for Current Measurement
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- เผยแพร่เมื่อ 30 ก.ค. 2024
- Clamp meters, how they work and how to use them.
Includes a modern example by Fluke, and two older ones by Sangamo Weston and Ferranti.
Patreon: / jwflame
Contact info, sending stuff in etc.: xo4.uk/?YTT
Website: xo4.uk/?Cmp - วิทยาศาสตร์และเทคโนโลยี
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Hi JW,
That Ferranti clamp meter brings back some memories.
Back when I was a 2nd year apprentice, my boss put me on-call, now I only had an orange set of Duspols and a multimeter, as that was all I could afford on the wages of the day.
I was loaned one of them Ferranti clamp meters and one of (I think) the original wind-up 500V Megger test instruments.
Even in 1987, these instruments looked like they had been resurrected from the tomb, but hey, not once did they fail me, I sorted out a lot of problems with these two instruments by themselves, until I could eventually afford my own gear.
Some months later, a newer apprentice dropped the clamp-meter onto a concrete floor and it shattered into a million pieces, we were all pretty peeved about this, it was like the death of a close friend.
Excellent tutorial on clamp meter which is always needed. Keep the great work up.
I bought one of these 10 years ago and I thought it was faulty as I was testing on multiple wires ie just what you cleared up, LN&E. Silly me! thanks for your great generous videos.
Me too! Now I know.
Clear and instructive, thank you.
Thanks for the video I had a question on my test about looping 4times in a clamp ammeter this answered my question
Hey John.. !! kindly help me bro i am gonna for buy Meco 1008 trms clamp multimeter. does it better then UNI-T UT 203 and in same price others ? kindly tell me it's urgent?
could you do a video about grid fused spurs or how to apprach a kitche where multi fused spurs are required.
also video on different types of cable and sizes to use for what starting with domestic e.g outdoor indoor use.
Thanks for the information.
Any thoughts or tests on the Fluke non contact "clamp" meters ? Like the T6-600 ?
thankyou!!, I need to simulate very high current in a safe way, looping the wire will will WORK.
Great video, thanks!!
Hi John.
Why don't high quality Clamp meters have HRC fuse protection like their multimeter counter parts ? Even fluke doesn't seem to fuse clamp meters even though they measure voltage
Any information on this would be excellent
thanks again for your good work John
Maybe a childish question here but at what point does the N become without voltage in a circuit. Assuming the are 2 present loads on a single circuit and I took a reading of N and E after the second would that then be zero voltage
How accurate are these devices taking into account that the magnetic permeability differs from wire to wire depending on the type and thickness of the isolation used? Thanks!
Very nice. Thank you.
Not sure if you know this but fluke makes a clamp on meter now that will read voltage through the clamp part
Excellent Tutorial JW , would you have a video on the 2 Pen uni-t ut15c volt tester, wondering if its any Good??
Beautiful
Hi John as I'm not qualified would I be permitted to run cables to position and connect things like sockets or ceiling roses under part p thanks
Part P is just this: xo4.uk/x/part_p_requirements.png
so most people should easily be capable of complying with it. Qualifications are not required, although they may be useful.
where is best to get a uk line splitter or monitor tool suitable for clampmeter and small currents.
I bought cheapest single gang extension socket and exposed a section of split wires carefully. Purpose built splitters are expensive and only really a single model still being made
if you measure line and neutral and get a reading isn't that a sure sign of current leakage? as they aren't canceling each other out?
Yes, and that is one method of detecting earth leakage. It does need a clamp meter which can accurately measure in the 1mA range - many do not, including the Fluke one in the video.
General question: On a DC clamp meter, does shielding around the wire influence the measurement?
Hi John, how do I contact you with bits and pieces, you doubtless have noticed I be tended to contact you via the video comments section, is there another way?
I actually have a question if I might seek your opinion, kind regards Warren
th-cam.com/users/jjwardabout
John Ward Hey John the link you sent doesn't work
John also has a Facebook page... Which I've already messaged him on, though I'm still awaiting a reply, but he's obviously a busy guy and it is the Xmas break.
a lot of people would like to see an old simpson meter demo.old electricians didn't have all the tools of today,good video,
Nice one. That Ferranti 'tong' meter meant business. Easily safe for Cat. VIII (!)
Even with the plug-in devices available, it's a pity that no one seems to have found a way of measuring the current in a flex containing both L + N conductors. Unless it just isn't considered to be worth the R & D.
Strange. With magnetic coupling to sense a current and then power electronics to track the rise and fall of that current, it seems (that is should be) quite possible to calculate the value of the current anywhere on the sine wave, positive, or negative. Obviously a suitable timebase value needs to be used to be able to track whatever the frequency of the AC being measured is.
We've done without for this long; so I guess a properly working device isn't going to happen soon.
The problem is having something which can detect the magnetic field from one conductor while ignoring the opposing field from the other conductor. In a flex or cable the two conductors will be very close together so it is exceptionally difficult to design a device to measure only one of them.
I think that this is just one of those 'challenges' that provides some thinking exercise for those quiet moments. :-)
With the availability of plug-in measurement devices for mains-powered equipment, I guess that manufacturers just don't see any worth in R & D spending to overcome the cancellation-effect caused by the proximity of the conductors in a normal flex.
Give me the rest of my life and I'll give it some thought!
@@jwflame And those condustors are usually helically wound within the flex itself.
How do the open ended meters work
Hall effect sensor, there is usually a line or mark where the sensor is which is also where the wire must be placed for accurate readings. On the Fluke ones, it's at the bottom of the U shaped slot.
Why can't you use a single probe like the clamp but smaller range. Contact probe so it's maximum closeness not conducting to circuit. Are 2 probes always required for bridging circuit. Couldn't pass load in and out of single probe in single contact point
Thought you were going to take it one step further John and show the new ones that measure DC current.
I've used a cheap UniT clamp meter for DC for a few years for automotive stuff. Seems to work fine. Although can see a bit of drift at low currents, device always needs reset before use. No idea how accurate it is, but seems ok for a quick test
@@blow0me Even expensive DC clamp meters need to be zeroed before use.
I've got a 5 year old Uni T and a much newer Appa/Amprobe/RS components one which is a much nicer meter to use, but they read about the same.
I'm setting up a DIY woodwork shop and want to measure the current each machine is drawing. I was thinking of getting a clamp meter like the one in this video BUT at 8.14 in this video you referred to 'one of those monitor things you can just plug in....because they are fairly readily available'. If that is what I need to get, please let me know what it is. Thanks
One random example: www.screwfix.com/p/energenie-ener007-energy-saving-power-meter-socket/3477h , many similar ones available.
When measuring DC,why do u get two different readings if u turn the clamp meter around?
DC clamp meters must be zeroed before each use and after moving them to eliminate the effect of the Earth's magnetic field and any other magnetic fields nearby.
Moving it without zeroing again will give incorrect results.
@@jwflame ohh, ok thanks much. Was measure short circuit current from a pv module and was getting like 6.6A and when i flipped the clamp meter i was getting around 2.1A.
What would you need to use a clamp meter for in a domestic installation? really great videos, thanks for taking the time to make them.
Current measurement for a single circuit, or the entire installation. The main advantage is that you don't have to disconnect any wires to measure the current.
Especially with the ones that have a minmax function (which most better ones do now) it's the sort of thing that you might leave on someone's meter tails for 24h to see the max demand to know of their incoming supply needs upgrading before any additional circuits are added (such as an electic car charging point which can draw significant current )
@@dasy2k1 Which is similar to the Energy Efficiency Module that is supplied by British Gas and other ESPs... Only that is a permanent installation and does not give readings in amps, only watts.
Being a heating engineer I normally use mine to prove immersion heaters are working
Some of the old clamp meters were just a moving iron movement, the magnetic field of the wire did all the work. I used to have two like that one went to 30 amps and the other was 400 and 800 the ranges were made by a stand off bracket on the back of the meter the furthest out being the higher range. Might still have them in the shed somewhere.
i used to have 2 ones for car use, one that measured 30 a and one 600a, to measure alternator and starter current, very simple, measured into the postive and negative so you always got a measurement. just lay on the battery wire to see how your alternator is coping etc
Sir plz can you say how to check that the neutral coming from transformer is weak or strong?🙏🙏🙏
I'm a newbie, recently bought the cheapest most useless single gang extension plug with no actual extension. Just enough to remove enough insulation and split the wires for a clamp. I did for a second think the meter was faulty when I tried it on full power cable. Didn't take me long to realize in fairness
I'm sure that AVO brought out an 'add-on' clamp module that could be plugged into the ampere terminals of a standard multi-meter.
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Very simple device to contstruct really and totally safe to use. Also the British Gas - Energy efficiency display module, that is available to anyone, but comes free with a contract, uses the same technology, as one has to place a current sensing coil around the line tail from the house meter to the consumer unit. This coil, in turn, feeds a wi-fi transmitter, that talks to the display module. The display does not show amperes however, but gives a reading in watts.
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Many (uninformed) have been caught-out trying to read the current flow in a multiple conductor AC flex...lol
how much do you pay ????
....... Ferranti stolen from Dr. Frankenstein's lab.
Save your money and buy one from uni-t they are the same and just as good as well as a dam lot cheaper I have used uni-t test instruments for seven years now with out any problems and I will not be going back to the big brands any time soon
Ya made that mistake John thought it would tell me what power in plug wire to tools
J.W. !!!!!!!!!!!!!!!!! Crackin video mate, but slow down and enunciate a little clearer, Sir, Thank You 🙄
Just use common SENCE PEOPLE think about that a while
Ah thast's not true you too ???
Who are you replying too?
Analo
Analogue = style .... digital maybe more accurate but = Zero ....