From the service manual, i see that the nominal current for this machine is 66 A.

When I do a simple calculation to go from HP to Amps, I get 46 amps (I used 460 volts, 3 phase, pf = 0.9

You can use a handy calculator like this: http://www.engineeringtoolbox.com/electrical-motor-calculator-d_832.html

So what are those currents you post? I see 4 measurements? Can you measure all three phases and send those to me?

If these are just some measurements over time, than it looks ok.

What often happens with older machines is that the overload relay becomes old as well and trips at a too low current. Or the alarm contacts become old and make bad contact sometimes. In this case you should replace the overload relay (also called 'thermal block').

Good luck!

Cas