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QUESTION:
Can I use multiple contactors to increase their capabilities?
ANSWER:
You can parallel contactors, however, they don't necessarily share the current evenly. That means one could take too much current, and eventually weld.
To do this properly, each contactor should be fused with a carefully chosen fuse that will protect the contactor! I have probed Kilovac before for the data that would allow for making this sort of decision, but they haven't provided it. Fuses' spec sheets show how long a fuse will take a certain current. The information needed about the contactor is the time vs. temperature curves that show how long the contactor can take a certain current before the tempertaure rises to a level that could weld the contactors. The fuse should be such that it blows before this temperature is reached.
I prefer the SW-200 style contactors, as you can inspect the contacts. They are only rated for 96V though, so to stay within specs, you need to put units in series to get to whatever voltages you're operating at. You can then parallel series groups of contactors to get the current ratings you're after. Enough in series to accomplish the voltage requirements you have, and enough sets in parallel to keep you in a safe range on the current-carrying capabilities.
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