Networks Analysis and Synthesis - Engineering

Q1:

A 3 phase balanced supply feeds 3 phase unbalanced load. Power supplied to the load can be measured by using
  1. 2 wattmeter
  2. one wattmeter
  3. 3 wattmeter
Which of the above statements is correct?

A 1 and 2

B 1 and 3

C 2 and 3

D 3 alone

ANS:B - 1 and 3

A minimum of 2 wattmeters is required to measure 3 phase power. Of course power can be measured by putting one wattmeter in each phase.