Great photo's Pauluk, Indead that was a mammoth task to build that computer, good too see that with will a lot of things can be made fully electromechanically. It takes a bit more space, but hobbies are great time spenders, and a challenge to complete something different. Also the cabinet making has been done very professionally. Excellent!!
The product of rotation, excitation and flux produces electricty.
IBM built relay machines up until the late 50s and early 60s. Something like a 407 accounting machine read cards in, did fairly complex computations on the data and printed out the result about 120 cycles a minute. It was one transaction at a time, which may involve several cards to complete then print out the result in a report, checks or whatever the desired output would be. This was all done with relays and mechanical ratchet counters. This required the cards to be sorted and colated in the proper sequence (perhaps the first being the data on who the customer was, the next being the history and the rest being current charges or payments) and that happened on other machines. It was an interesting bunch of stuff to work on. We also had 357 data entry systems that used relays as scanners, registers and counters. I wonder if the guy who built this thing is an old retired IBM guy ;-) I made a tic tac toe computer with relays that was unbeatable. The best you could do was tie. I used to make lots of relay stuff when I had lots of relays around. I prefer 4000 CMOS when I make things these days
It's amazing just what can be achieved electromechanically. Just think of the complex register-translators, markers, and other circuitry which was used in pre-electronic telephone exchanges for another example.
You'll notice that he did mske one concession, and that was a 32K x 8-bit static RAM I.C. Trying to implement that with relays would have really made things big!