i) Assumptions:-

a) The 3-ø system consider here is a load, which is delta connected.

b) The phase sequence is R→Y→B.

c) It is balanced load.

d) The p.f. of each phase is logging.

ii) Connection:-

iii) Proof:-

Reading of wattmeter W1

$W_1=V_{RB}I_{RL} \cos(\angle between V_{RB} \& I_{RL})=V_LI_L \cos(30^0-\emptyset_{ph})$

Reading …