3-Phase to Single Phase

In Delta formation the Singe phase voltage is the same as the line voltage(3 phase)

So if you have a 3 phase 208v supply, then your single phase voltage is also 208v.

If you wish to change this voltage you can either use a single phase to single phase transformer, or a 3 phase to single phase transformer or a 3 phase Delta/ Star transformer to create a mid point and neutral on the secondary side.

I could show you easier with a drawing but I haven't found out how to import it in here yet.

Can any tell me how to import a drawing or picture into these posts.

In the editor window look for the small green camera.

Click on it, and in the next window click on browse.

Find your picture and Open

After it is inserted, you can mannually move it around within your text using your mouse

Single phase to ground or neutral will be 120volts

Thanks for the tip on the Editor window I never noticed it before!

Don

On delta only 2 legs will go 115 to ground or neutral the third usually the center phase will read 208 to ground

can u send me the drawing to ma email directly?

tanbch@gmail.com

You should all so have 110 single phase voltage. One leg to neutral

HA HA

V= I*R

Otherwise be more indeath with what you want!! there lots of formulas out there.

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Thank you and good night

Star connection

Ip = IL

VL = 3 square root * IP ( or reverse if you have the line voltage)

Detla connections

VL = VP

IL = 3 square root * IP

3 phase power = 3 * VL * IL * cos (PF)

need more info on what you try to achieve!!

___________________

Thank you and good night

Normally, if you have 208 v 3 phase it comes from a Y connected secondary, which has 120 to ground/neutral. For a single load you can go from phase to phase (208 v) or if Y connected, phase to neutral.

There is a formula for 3 phase Y connected transformers. Phase to phase voltage over (constant) 1.732 equals phase to neutral voltage, (208/1.732=120). Conversly, single phase voltage times 1.732 equals phase to phase voltage (120 X 1.732 = 208).

TA TA

First, is the single phase motor a 208vac motor? You don't say. If so, all you need to do is to use 2 phase legs of the delta connection to connect the motor. If it's 120vac motor, see if your/the transformer has a center tap (bastard leg) which can be used as a false neutral/ground and give you 120vac. Or use a 208vac primary to 120vac secondary single phase tranformer to get 120vac.

Typically delta connections at 240 volts nominal (where I'm located) are 240vac and wye connections are 208vac.

Single phase 208 v is line to line, no neutral. Most 240 v motors are rated 200 to 240 volts. 208 runs higher amperage at load, same power. Check the motor nameplate.

RichH

At 208 v, don't forget that you need a 2 pole switch to kill both lines.

Are you sure you have Delta-Connections NOT "Y" or "STAR" connections? Note: "Y" or "STRAR" have "Neutral-connection" also & Voltage between "Neutral-connection" & any Ph will be what will be Ph-to-Ph in "Delta", In your case you have to run your motor on 208V & it should be so rated.

how we can calculate maximum demand of 300 kva connected load and devercity factor is 0.8.