Little close? Nah. If there are 3 taps it only needs to dissipate 50W, in any case any more than that results in requiring a MUCH larger heatsink anyway
Yes you are right... after I posted this I thought about what I said and realized that this is one of the reasons they have the four different bus voltage selections, to keep dissipation down, use small heatsink, "cheaper" transistors, smaller ballast resistors, etc.
One thing I am going to test is when the relays switch (changing voltage setpoint), does the output bounce around? (this is a question that I am going to try and resolve).
Another thing... when switching the output on, is the relay switching causing the overshoot on turn on (another question I am going to try and answer)?
This would indicate to me that the output should be enabled FIRST, then applied to the binding posts after a short delay (after the supply has settled), and I might just makeup a delay to do this so I don't cook something from the turn on overshoot.