Which clamp meter do you recommend? 1

[yalgaar]

I maanage a computer datacenter. There are several servers connected to PDU's.

1) I need to know the current flowing through the power cables that connects from the server to the PDU (this is generally in the range of 1 amps - 5amps)

2) I also need to know the current flowing through the power cable that connects from m PDU to the wall. This is generall in the range of 5 amps - 20 amps)

So basically I never need to measure anything more than 20AMPS. But accuracy is important. If the actual power draw is 2.5AMPS, my accetable range for the meter to tell me would be anything between 2.25AMPS - 2.75AMPS)

I looked at several clampmeter online but did not quite well understood it's electric specification when it comes to resolution and accuracy.

I wouuld really appreciate if somebody could please explain.

 

[dpc]

If you're talking about a multiconductor cable, just be aware that putting the clamp around all the conductors will result in a zero reading since the net flux is zero. To get an accurate reading you have to put the tongs around just one hot conductor. But maybe you're already aware of this....

You also have to consider the harmonic current (distortion) in the current going to a switched mode power supply such as in a computer. To accurately measure this, you will need a more sophisticated device that can read rms current or fundamental current only.

To a large degree you will get the quality you pay for.

"The more the universe seems comprehensible, the more it also seems pointless." -- Steven Weinberg

 

[racobb]

There are many good meters available, Fluke is the first that comes to mind, but there are many others. Do you need to measure harmonics?

My real question is: You talk about the power cables suppying the equipment. To be able to measure the amps you must be able to isolate the "hot" and the "neutral" to measure the amps. If you are able to do that then most any clamp on meter will do the job, unless you need more detailed info.

Point is you cannot clamp on the entire cable and measure the amps.

Alan

Democracy is two wolves and a sheep deciding what to have for dinner. Liberty is a well armed sheep!
Ben Franklin

 

[waross]

And if you are trying to measure power and don't know the power factor, you may be somewhat misled by amperage readings.

Bill
--------------------
"Why not the best?"
Jimmy Carter

 

[busbar]

There is an advantage to using a current probe that is cable-connected to a multimeter, and that is you can get to a wire in an area that is not well lighted, where the multimeter display is “outside the box.” Examples are:

http://www.aemc.com/products/html/view.asp?id=20401&dbname=products

Just make sure if you buy a probe that has milliampere or millivolt output, that your meter is configured accordingly.

 

[ScottyUK]

Those who believe you can only use a clamp meter around a single core and not a complete cable might be interested in this instrument from Megger: MMC-850 . I haven't used one so I can't comment on how good it is, but it's an interesting idea and might be really useful in somewhere like a data centre.


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If we learn from our mistakes I'm getting a great education!

 

[racobb]

Interesting, although the cable sizes are limited, they are bound to get better....thanks for the link!

Alan

Democracy is two wolves and a sheep deciding what to have for dinner. Liberty is a well armed sheep!
Ben Franklin