Current Measurement Device

[AdamAReid]

Hello,

I am looking for two current measuring devices. They both need to be remote (non-handheld), and send out a signal (such as analoge voltage) that can be interpreted by a data logger, for transmission into a PC.

The first needs to measure the current being drawn by a 24V DC Motor (drawing between 0-7amps).

The second needs to measure the current being drawn by a 5.5kW AC Motor (0-14amps).

I was thinking about some kind of current shunt module.
Any ideas (or recommend some informative websites?). I've heard of sensors that "wrap" around the supply cable and read current. Would such sensors be more appropriate?
Thanks,
AAR

 

[Lewish]

Take a look at

http://www.amploc.com.

Then, further clarify what you mean by "remote".

 

[AdamAReid]

Thanks Lewish,

By remote, I mean it needs to be stand-alone... I can't be there to hold it or position it. It needs to be something (non-hand held) that I can affix to a cable to read the current going through it, and, it needs to send out a signal that a simple datalogger can read (like, say, voltage increase with current increase) and send to a PC.
Looking for something small and cost-effective.

Thanks agian for your advice,
AAR

 

[buzzp]

There are many options but to keep it low cost try Load Controls Inc (True rms measuring) or if TRMS is not a concern then go with someone like SSAC, Diversified Electronics, or Veris Industries. Good luck.

 

[Briank7]

Both the measurements can be done using a current transformer. The ac signal can be measured using a wired-in transformer or a "split core transformer" if you don't want to disconnecet the circuit. You can also get a "DC"current transformer (this is a form of dc-dc converter) for the DC signal. Most electronic vendors such as Maplin or Electrosonic sell these. You might use a shunt for the DC signal but this depends upon the earthing arrangements and in any case its not a bad idea to use transformers to isolate your supplies from the PC. If you use a current transformer do remember to always terminate the secondary in some resistance for safety reasons.