meter accuracy

[ronald]

1.most of our meter are electronic. Just wnat to know if it be possible to adjust its accuracy if it be found to be below its allowable tolerance.

2. can anybody have the idea for any conventional testing equipment for testing the accuracy of a current transformers. maybe a circuit of it.

any reply would mean a lot.

 

[charlie tuna]

Re: meter accuracy

utility rated meters must be within two per cent accuracy and it is the responsibility of the building's owner or that company who is billing the meter's use, to maintain the meter within these tolerances. the meter's owner is allowed to add three per cent to the power bill to put asside for meter testing and repairs. check with your public utilities commisioner's office for the latest rules...

 

[ronald]

Re: meter accuracy

thanks charlie. actually i know that. my concern is, is it possible to adjust the accuracy of meter thru calibration if its already below its %accuracy of plus/minus 2. my friend says that electronic meter's accuracy cannot be adjusted, its already set by the manufacturer of which i dont believe, maybe there ways to adjust.
we have conducted an accuracy test on our meters and one unit has an accuracy of 93% which is not favorable. we have already replaced it.
again thanks.

by the way, you any idea on how to test the accuracy of current transformer.

 

[charlie tuna]

Re: meter accuracy

i have worked in a meter re-build shop (hialeah meter company) and watched as they checked the accuracy of meters (none electronic) and it is a major operation --- you better be a meter company to check accuracy because it is a major investment to have one of these instruments in your shop!!!

 

[charlie]

Re: meter accuracy

Our meter shop can adjust mechanical meters and check the accuracy of all meters. However, the adjustments to electronics take special software that our meter shop does not have. We send new meters back to the manufacturer or junk the older meters.

 

[gregoryfast]

Re: meter accuracy

The "Handbook for Electricity Metering" covers testing CTs in great detail on pages 346 to 358.
There are 3 basic tests. These tests are saturation, burden and ratio tests.They all require expensive test equipment.
If you have or can make a constant current source, such as 1 heater with one conductor running throught the CT or in series with the CT (depending on type), you can then use an ampmeter to measure the secondary output. It will give you an idea of the accuracy. Again, depending on type of CT, you may be able to do this test while the CT is in use.

 

[brian john]

Re: meter accuracy

Most electric tesiting companies have the equipment to test kwhr meters. In lieu of the above any power quality meter that measures KVA,KW PF and KWHR can be utilized to get a close measurement of accuracy. You can monitor for and hour and do a comparsion reading. This is assuming you keep your test equipment calibrated
(as any quality testing companny would.

Any meter digital or analog can be out of cal.

 

[ronald]

Re: meter accuracy

thnaks for all your replies. it gave more ideas. God bless.