I am used to 6, 12, 24, volts DC. But why did/do diesels have stuff like 32 and 64 volts? (OK, 64 = 32 x2)
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The watts reqired for the starter, for instance, at the higher voltage of 32 over 12 or 6 will allow the use of smaller wire. Same for any other 32 or 64 volt equipment on the engine. Smaller gauge wire needed.
Ed M
OK, I can understand the concept of samller wire for larger voltges. But why 32 vs say, 48, which is a multiple of standrd high power batteries today (12). Or do trian bateries have a differnt multiple system: 16, 32, 64?
From what I can see, the locomotive batteries are built on mutiples of eight cells, which gives you 16 volts, two batteries or one big 16 cell 32, as so on.
So your six, twelve and 24 would also be 2 volts a cell.
I guess the real question would be why wet cell batteries are built on 2 volts a cell.
And I don't know the answer for that one.
Ed M
Ed is correct with his multiples of 16. Diesel electric equipment from EMC/EMD has always been 64 volts, for the low voltage control system, from the batteries. When the diesel engine is running and the auxiliary generator is "charging the system", the voltage is then 74 volts for the entire low voltage control system.
Prior to the days of electric and air engine start motors, mounted on a ring-gear as part of the "fly-wheel/coupling disc", the prime mover was cranked/started by separate windings built into the main generator (DC). It required pretty high current (over 300 amps in the winter), to cause the main generator to crank the diesel engine, thus the requirement for a 64 volt "starting system".
I have never seen any diesel electric units with 32 volt DC systems, only steam locomotive lighting circuits.
And Lithium ion chemistry produces 3.7V per cell-- mostly used in cell phones and new cordless power tools and hybrid/full electric cars.
