X1-X4: 1200-5, 2.5L800
X1-X3: 800-5, 2.5L400
X2-X3: 600-5, 5L400
It seems the CT has three ratios on the given tap connections. However, if connect the taps as below you may get:
The questions are:
1) is this a common practice to get more CT ratios other than just go by the tap connections shown on the nameplate?
2) having above given information how do you think the connections in 1) would affect the accuracy and the knee point?