Spin Problem 3-17,3-18

[kduff70]

[SIZE=10.5pt]I attach the spin diagram and the two question I’m having trouble solving.[/SIZE]

[SIZE=10.5pt]I'm not to familiar with the ladder logic involved in these two problems but I assume the first problem 3-17 close "Z" when "V" is pushed and that gives me the equation IN = -(IA+IB+IC) But when I solve this problem using the ABC sequence I get the right magnitude of 83.4 Amps but my angle <57.[/SIZE]

[SIZE=10.5pt]For the second problem 3-18 when the question ask to close in "T" I'm not sure how they came up with the equation [/SIZE]

[SIZE=10.5pt]IN= -(IB+IC)[/SIZE]

[SIZE=10.5pt]but assuming this is the correct equation once again I get the correct magnitude 96 Amps but my angle <22[/SIZE]

[SIZE=10.5pt]Can some please direct to the proper way to solve these type of problem?spinprob.pdf[/SIZE]

 

[Moonlight]

[SIZE=8pt]For both problems I get the same but "positive" magnitudes and different angles using the ABC sequence. [/SIZE]

[SIZE=8pt]I think in the problem 3-18 when the button T is pushed the relay Z will de-energize making Z contact open this will disconnect the motor from phase A to neutral, therefore IA=0.[/SIZE]