So while the electoral college might have also functioned as a way to redistribute votes within a state... I don't think that was its main purpose.
https://en.wikipedia.org/wiki/Faithless_elector#List_of_fait...
As with so much in American history the explanation involves slavery but judging from the downvotes here, that wounds everyone's pride a bit.
...other than the large numbers in the late 1700s and early 1800s, you mean?
And in any case, "intent" and "actual practice" were pretty different here. But that doesn't mean that the Connecticut Compromise [0] (which split the US legislative body into the House with representation apportioned by population and the Senate with set representation per state) was solely or even primarily due to slavery. And once you had that, using the total of Senators and Representatives for your number of electors makes a good amount of sense.