test equipment suggestions

[hardworkingstiff]

FYI, dock pedestals for boats can be purchased with electronic KVA meters that consist of CTs and an electronic meter that pulses to a counter. I have had a few requests for verifying that the meters are working correctly.

I am considering building a test device that basically would have CTs connected to an electronic display. A cord connection to the power pedestal would run through the CTs and into a load bank. Then it would be a simple matter of checking my consumption reading with that of the power pedestal.

Grainger has some pretty neat looking equipment in their catalogue that I believe will do the trick.

My concern is how I can document that my "homemade" equipment is calibrated. Any suggestions? How often would you think the calibration would need to be verified? Do you believe putting a known load on the device for a specific time (to get KVA) would be an accurate calibration check? I don't believe it would be necessary to have a 3rd party certify calibration, but if not too costly would be beneficial.

Thanks in advance to all the help.

 

[bob]

Is the request to verify the KVA or KWH? Why not use a clip on amp meter
and volt meter to verify the KVA? KWH would require a meter that has been calibrated accurately.

 

[hardworkingstiff]

Is the request to verify the KVA or KWH?

The request was to verify the meters work, I'm pretty sure they are KWH meter system.

Why not use a clip on amp meter
and volt meter to verify the KVA?

That would require (IMO) too much human subjective observation.

KWH would require a meter that has been calibrated accurately.

Yes, and the meter calibration is the part I'm trying to figure out.

 

[jghrist]

FYI, dock pedestals for boats can be purchased with electronic KVA meters that consist of CTs and an electronic meter that pulses to a counter. I have had a few requests for verifying that the meters are working correctly.

I am considering building a test device that basically would have CTs connected to an electronic display. A cord connection to the power pedestal would run through the CTs and into a load bank. Then it would be a simple matter of checking my consumption reading with that of the power pedestal.

Grainger has some pretty neat looking equipment in their catalogue that I believe will do the trick.

My concern is how I can document that my "homemade" equipment is calibrated. Any suggestions? How often would you think the calibration would need to be verified? Do you believe putting a known load on the device for a specific time (to get KVA) would be an accurate calibration check? I don't believe it would be necessary to have a 3rd party certify calibration, but if not too costly would be beneficial.

Thanks in advance to all the help.

You could possibly do the testing yourself if you had the right equipment and procedures. Simply connecting a single known load will not adequately cover the requirements for accuracy at various percents of full meter load and power factors. I suggest going to http://themeterguy.com/ and browsing.

 

[jdsmith]

Assume that you have a homemade verification setup that has been calibrated somehow. If you detect a metering setup that isn't reading correctly, what is the next step? Do you have to convince anyone that it's reading incorrectly, or do you just fix it/change it yourself? If you have to present any evidence, other than telling the owner that one was incorrect and you need $$ to fix it, they might not like the homemade setup, regardless of accuracy.

On a different train of thought -
Are you looking for a meter that will perform the same function as the amp clamp and voltmeter combo but take care of the calculations itself, and read out in kW or kWh? I have a Fluke 43B power quality analyzer that would do that all within the one device. I'm not sure if this is the answer you're looking for though.

Some of this more expensive test equipment can be found on ebay, brand new, at prices nearing 50% off of normal retail. Used equipment can be around 30-40% of retail, but it really needs calibrated plus you run the risk of having further problems. I'm using my fancy toys for my own learning experience more than anything, so this is the only way I can justify buying them.

 

[cschmid]

We can go to the power company and get equipment from them and the owner can have them come out and verify their equipment as well..they have all the equipment for this..when I had them do it for me they had a machine that recorded it and he downloaded it and gave me a printed report..

 

[zog]

I dont think a calibration you do yourself proves much, thats the whole point of 3rd party calibration. As far as how often, annually for digital, semiannual for analog.