3-Phase 3 Wire Meter
A 3-phase 3 wire meter has 2 elements of each category on the other hand of 3 elements as in the case of 3-phase 4 wire meter. The primary principle of operation is the similar as that for 4 wire meter. The torque produced through 2 elements is equivalent to each other while power factor (P.F.) is unity. On the other power factors, the torques produced through the 2 individual elements is not equivalent and is of varying proportion. B phase element generator more torque at lagging power factors, although the R phase element produces more torque at leading power factor.
This particular feature could be made use of to search out the P.F. of the load current of the consumer for the reasons of checking at site. Power factors less than 0.5 are denoted through the reverse running of the meter along with only the R element in operation. Commonly, 3-phase 3 wire meters are not used in recording consumption of LT power consumers for the simple purpose that the lighting load has to be properly connected on one of the phases R or B. Or else, if it is connected on the Y phase, where no current coil is provided, energy consumption would not get recorded.