ANSI C84 is the industry standard that covers our nominal voltages. 120, 208, 240, 480, 600V have been the standard for more than 50 years.
Read the forward for a little history.
http://www.nema.org/Standards/ComplimentaryDocuments/Contents-and-Scope-ANSI-C84-1-2011.pdf
Terms like 110 and 115V are left over from the oldtimers that used to mentor us. We have kept the bad habits alive.
I've previously commented The complexity of the different voltages.I cringe almost daily at the 110 volt terminology being used by electricians both young and old, even when the system is 208Y/120. :slaphead:
Aircraft I assume?We build load banks for nominal 200/115V Y systems. Of course they are 400 Hz.
Yes. Really sounds sloppy to me. Unless it is a movie line being quoted - "220, 221, whatever it takes"I cringe almost daily at the 110 volt terminology being used by electricians both young and old, even when the system is 208Y/120. :slaphead:
OTOH, a lot of three phase motors say 460V on them.
OTOH, a lot of three phase motors say 460V on them.
Motors and most other 'loads' are usually labeled with utilization voltage which is about 4.2% below nominal (e.g. 115, 230, 460, and 575)
Connector type equipment (e.g. plug or screw thread) are usually labeled with a maximum nominal which is about 4.2% above nominal (e.g. 125 and 250).
The NEC says we should be using nominal levels when we mention voltages. (e.g. 100 definitions, 110.4, and 220.5(A)). Therefore strictly speaking, saying 110V violates the NEC.hmy:
That's the only reason. 460V gives a Vd from the nominal system 480V - Which is normal at the end of the feeder.... I think part of the reason they rate them at the voltages Jim mentioned is that it allows for some voltage drop from nominal and this will still get the actual values near the nameplate values.
Could be, but most places around here with 480 volt nominal service generally run around 495-500 volts at the supply end, and unless you have a pretty significant voltage drop are still above 480 at the motor. And 240 volt services generally run 246-250, 208 volt services typically about 215 - 218 volts.That's the only reason. 460V gives a Vd from the nominal system 480V - Which is normal at the end of the feeder.
I've previously commented The complexity of the different voltages.
I can sort of understand where the 120-0-120 comes from. Ignoring the earthing, it is a three wire system. Balance the 120V loads and the current in the neutral conductor is minimised.
But if everything, lighting and domestic appliances were rated for 240V it would be a two wire system wouldn't that greatly simplify installation?
And wouldn't it remove, at a stroke, the seemingly ubiquitous problem of lost neutrals causing conflagrations and consternation?
Ever since I started I have always wondered why everything wasn't straight 240 volts. It never made any sense considering most other parts of the world have low cost 240 volt appliances. Still blows me away, especially considering how much people screw up the neutral here or just don't get it.
I've previously commented The complexity of the different voltages.