control transformer wiring

[testsubject]

I would say that that would be a reasonable request

 

[rsdoran]

First let me state I was being dramatic, overall I am not confused with the numbers involved. One of the issues I have come across are devices stating 420vac +/- 10%/ That means the device can operate between 380 and 460 (approximately). Know what happens when actual line voltage is over 490vac?

My rant was about their being too much discrepancy/inconsistency in general pertaining to voltage(s).

 

[DanielCamacho]

I hope I never get the chance to have 40 years expierance...

The only thing I have 40 years of experience in is breathing...
Thank God for guys like Lance who will actually share what they know...

Like you Mike, I hope I am still kicking for another 40...

 

[Lancie1]

Thanks, Daniel,

I feel very lucky to be where I am. I retired from a regular job at age 42, and haven't held a 9-to-5 job since then. I have kept on working though, part-time and in spurts. It is a lot easier when you know you don't have to, and that you can walk away at any time.

 

[Rod]

Lancie,

You said a transformer will deliver the nameplate voltage?
Isn't that true only if it is an 'auto-transfomer'?

I don't mean to nit pick here, but...

Rod

 

[Lancie1]

I was talking about both the transformer Input voltage and the Output voltage. If the input voltage is the same as the transformer nameplate input voltage, then so will the output voltage be same as nameplate output, because transformers have a known turns ratio. Now, for many transformers, there are the voltage taps to consider. If the input voltage is high or low, then the taps allow the output to be adjusted. This is where the variations in level come into play.

 

[Leadfoot]

I would like to add this.

208/127 usually means the source is 3 phase grounded neutral.

220/230/240 usually means 3 phase floating could be delta or wye.

440/460/480 usually means 3 phase floating could be wye or delta.

480/277 is wye with the center tap being used as a reference. Old single phase dc drives used this.

Once upon a time the frequency was called cycles per second, how it is called hertz cuz it does when you touch it.

60 hertz wave length is shorter than 50 hertz which allows smaller packageing and less filtering needs when converting to dc.

 

[darrenj]

I would like to add this.

208/127 usually means the source is 3 phase grounded neutral.

220/230/240 usually means 3 phase floating could be delta or wye.

440/460/480 usually means 3 phase floating could be wye or delta.

480/277 is wye with the center tap being used as a reference. Old single phase dc drives used this.

Once upon a time the frequency was called cycles per second, how it is called hertz cuz it does when you touch it.

60 hertz wave length is shorter than 50 hertz which allows smaller packageing and less filtering needs when converting to dc.

from a sparky's point...

i have never heard it put as 208/127..just 120/208..

to 60-50 Hrz point is just going to start a war with the people in across the sea!!!

220/230/240 means single phase to me

isnt 277/480 the standard voltage in the states?? (3 phase)

 

[LadderLogic]

There is no such thing as "standard" voltage in the States - since very few things have ever been standardized here (it is just a different philosophy as compared to, say, European union).

"Widely used" would be a more proper term. Unlike 60Hz frequency which would be hard to change (all rotating things depend on it etc.)

One may encounter 460V, 220V and 208V 3-phase systems almost equally often in industrial facilities in USA... kind of whatever the old habits were. Generally speaking, though, the newer plants are usually wired for 460 - great savings in copper, after all.