42VAC control voltage?
42VAC control voltage?
(OP)
I have just run across a tunnel boring machine made in England that is using 42VAC as a control voltage. I see that several control mfrs offer that as an optional (but never in stock) control voltage, but I am curious why someone would specify such an odd ball voltage. I'm doubtful that someone just pulled that number out of thin air, so I have to assume that there must be some sort of valid engineering justification or some problem that was solved by using 42VAC, I just can't think of one. Anyone know?
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RE: 42VAC control voltage?
old field guy
RE: 42VAC control voltage?
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If we learn from our mistakes I'm getting a great education!
RE: 42VAC control voltage?
Bill
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"Why not the best?"
Jimmy Carter
RE: 42VAC control voltage?
SELV actually always was 42 V maximum for so long time that my technical expertise once was challenged when I mentioned 42 V as the limit for safe voltage. Eyebrows up. "50 volts, you mean?" Of course I did, but since 42 is what you have and also is the nominal voltage, I had assimilated it as the standard.
Gunnar Englund
www.gke.org
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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
RE: 42VAC control voltage?
"If I had eight hours to chop down a tree, I'd spend six sharpening my axe." -- Abraham Lincoln
For the best use of Eng-Tips, please click here -> FAQ731-376: Eng-Tips.com Forum Policies