One notable thing about the constant power draw of ECL and Cray-1 in particular is that power draw is constant enough that the logic supply is unregulated, just rectified and filtered output of 400Hz transformers (placed physically in the "bench part" of the chasis). What is regulated is the 208V/400Hz supply for the thing (produced by the motor generator shown in the article), but regulation of that IIRC involves manual turning of physical knobs during installation/maintenance and is more about compensating for unstable mains on the input side.
