Multimeter review UNI T UT139C

[bijuif]

Hi saw this multimeter by UNI T ut139c over the internet and youtube. The features of this multimeter is similar to UT61E but  limited information is availiable on the net. There is one review of ut139c on youtube but not in detail. The review states this multimeter has got better input protection than UT61E and somewhat is visible in the teardown part. The multimeter posses a 60A current clamp option in this multimeter and this interests me but unfortunately there is no information about the usage or the accessory clamp. The official website of UNI T also do not have any information regarding this. Can anybody throw some light on this thread so that it will be helpful for all.  The link to video is posted below https://www.youtube.com/watch?v=3KP1pB4JdGw

[retiredcaps]

The multimeter posses a 60A current clamp option in this multimeter and this interests me but unfortunately there is no information about the usage or the accessory clamp.

The UT139C is discussed at eevblog.com/forum quite a bit.  I don't remember if anyone has the current clamp option, but you can read the threads over there and perhaps ask on the eevblog forum.

I have no need for such a clamp so I tend not to pay attention to those replies (if any).

[ProBang2]

Hello.

Sorry, I canīt get the exact point of your question. So excuse me, if there is to much information in the following text.

First things first:
How does a current clamp transducer works: http://www.powerguru.org/open-loop-effect-current-transducers/

The usage of an accessory clamp:
See the attached Pdf-File below. Just for your interest: I have scanned the manual of my old, heavy, reliable, built like a tank, Escort ECT 670 transducer. The handling should be anyhow similar.

Generally you can use this accessory clamps with every multimeter, which is able to do mV- readings.
With the Escort transducer (1A => 1mV) you can declare the mV readings straight as Amps.
With a current clamp, thatīs necessary for the UT139c, (1A => 10mV) you have to calculate a little bit (dividing by 10).
In the clamp-function does the UT139c the math for you and displays Amps. Thatīs less confusing.

Perhaps there is nowadays somehow in industrial enviroments a need for multimeters with separated current clamps.
But even there exists alternatives with integrated clamps. Martin did some reviews with such clamp-multimeters.

Some of Martinīs Videos about clamp multimeters:

Tutorial: How to use a clamp meter / current clamp ==> https://www.youtube.com/watch?v=nxhUwH70F_4
Electronic measurement equipment and multimeters - Part 2:Clamp meter ==> https://www.youtube.com/watch?v=z9wvUq6uBDw
Review: GTC CM100 1 mA to 100 A Low Current Clamp Meter ==> https://www.youtube.com/watch?v=1sq2WRGPABw
Review: ISO-TECH IPM 243 Power Clamp meter 600A AC/DC ==> https://www.youtube.com/watch?v=ggPk-zL6O9E
Review: UNI-T UT241 Power Clamp Meter ==> https://www.youtube.com/watch?v=RM4Ts-4_mTA
Review: UNI-T UT207A AC/DC Digital Clamp Meter ==> https://www.youtube.com/watch?v=XzxsJiYTIs0
Review: HT 9022 Power Clamp Meter - Pt1 ==> https://www.youtube.com/watch?v=PeUjXzdh8a0

There are many videos from others, too. For example these:

UNI-T UT204A vs Mastech MS2108, two cheap clamp meters compared ==> https://www.youtube.com/watch?v=ZqdTXfNfgR8
UNI-T UT203 Clamp Multimeter Review ==> https://www.youtube.com/watch?v=96d5-APZhww


IMO: A current-clamp with 60A range is pretty useless.

In Cat I and Cat II Enviroments:
- Measuring current on PCBīs or Breadboards is simply not possible.
- Measuring current flowing through wires with the clamp is possible, but:
- splitting the circuit and connecting a DMM in series isnīt difficult and provides more accurate results.

In Cat III Enviroments:
- Mains in house is secured with max. 16A fuses. (At least in Germany.) Any decent DMM should handle this, if itīs connected in series.
- Measuring Amps e.g. in a power cord is simply not possible. You have to separate the live wire from the others for measuring.
- A cheap energy-meters displays Amps, also Volts and Watts, for a much lower price.

In Cat IV Enviroments:
- I can assure you: I wouldnīt use any Uni-T equipment under those circumstances.
- The 60A-range is probably not sufficient.

Industrial Enviroment: Same as Cat IV.

Automotive use:
- Most circuits are fitting in the 60A-range, but measuring the current of a starter (100-180A) is impossible.
- Why fiddling with two devices, when DMMīs with integrated clamps (able to measure starter current) are available?
- The 60A-range is not sufficient for use with electrical car high-power-circuits.

Donīt let me be misunderstood: The UT139c is as a versatile DMM pretty useful and seems well built.
But, if it depends on the option to connect a 60A current clamp transducer, there are many better alternatives.

Greetings,


Hartmut

[bijuif]

Thanks for the in depth information given about the thread. i would look forward to it.