Three phase electrical power meter 2

[JPH001]

Can a three phase meter be used to measure single phase power accurately?

 

[busbar]

In a simple sense, yes. However, modern meters may "complain" in the process, and generate alarms for missing quantities. In a three-element meter, unused current and potential coils would be left unconnected.

 

[gcaudill]

busbar,

I do not know how a power meter works exactly. How does a power meter for single phase where P=IxE work the same for three phase where P=IxEx1.73?

 

[busbar]

Find a copy of the Electricity Metering Handbook, and study the 1-, 2- and 3-wattmeter methods of power measurement.

 

[DanDel]

gcaudill, remember, P=IxEx1.73 is for a balanced system with the same current in each phase; or basically, an estimate of 3-phase power. Actual 3-phase power is the vectoral sum of the individual phase currents multiplied by the individual phase voltages.

 

[jwbhabal]

Electric power in a 3 phase ckt can be measured by using two methods 1) 2 wattmeter method 2) 3 wattmeter method. In 3 wattmeter method in eachphase a single wattmeter in connected. So wattmeter reads power in that perticular phase. So for three phase total power will be = Rph + Yph + Bph. In 2 wattmeter method instead of individual phase wattmeter only 2 wattemers are connected but the voltage used is phase - phase and not phase to neutral. So we use either conventional electromechanical meters or static meters but for both these basic metering scheme remains same. If u are using 2 element meter then u cannot read single phase power accurately.cos remember the voltage given is phase-phase. But if in case of 3 element meter since each coil is independent one can only connect trhe perticualr phase current and phase voltage and meter will measure single phase power. In case of some static meters one may get phase failure alarm or some erratic readings. But try it.

 

[zohar]

Hi
In digtal meter that I am familear with their is no problem because the meter calculat the sum of the energy that it measure in every phase.
If u can read all the electrical parmeter like in the CVM family of Circutor or PM family of Satec u'll be able to see it by selecting the right cod.

 

[Shortstub]

Jwbhabal,
The 1-wattmeter case only works if it is used on a 4-wire system. The potential coil must be connected between the phase and the system "neutral!"

Busbar,
The potential coils can not be left disconnected, even if a 3-wire system. Their connection establishes the system "neutral!"

 

[jbartos]

Suggestion: Visit

http://www.wentec.com/unipower/archive/pdf/hpl405A3Parchive.pdf

etc. for more info